Blasthole Drilling in Open Pit Mining

Blasthole Drilling in Open Pit Mining

First edition 2009 www.atlascopco.com/blastholedrills

We’re redrawing the line between We’re redrawing the line between productivity and innovation. productivity and innovation

Introducing the new and expanded line of the Pit Viper Series drills from

Introducing the venerated new andPV-351, expanded line ofPV-271 the Pit Atlas Copco. The PV-275, and areViper beingSeries joined drills from by theCopco. all new The PV-235 series. AndPV-351, throughout the line, we’re crafting Atlas venerated PV-275, and PV-271 area being joined better user experience by improving your comfort, control and visibility. by the all new PV-235 series. And throughout the line, we’re crafting a Plus, our new power systems add to your bottom line with increased better user experience by improving your comfort, control and visibility. fuel efficiency. So, whether you’re mining precious metal or mineral, Plus, our new power systems add to your bottom line with increased follow the line and mine with us. fuel efficiency. So, whether you’re mining precious metal or mineral, follow the line and mine with us.

www.atlascopco.com Find out more at www.atlascopco.com/blastholedrills

Copyright © 2008 Atlas Copco Drilling Solutions Inc.

Contents Foreword 2

Foreword by Brian Fox Vice President Marketing Atlas Copco Drilling Solutions LLC

Front cover: Pit Viper 271 working in Southwest US copper mine. Photographer: Scott Ellenbecker

Talking technically 3 11 13 19 25 31 35 37 41 47 49 59 61 65 69 73 75 79

From gunpowder to Pit Viper Ergonomics and safety An introduction to surface mining Putting rotary drilling into perspective Automated surface blasthole drilling Tricone rotary blasthole drilling Optimizing the rotary drill string Increased productivity with DTH drilling Selecting the right DTH drilling tools Taking advantage of single-pass drilling Blasting in open cut metal mines Drilling in Arctic conditions The new mid range Pit Viper 235 Development through interaction - Pit Viper 270 Large diameter drilling – Pit Viper 351 Peace of mind The economic case for routine bit grinding Secoroc Grind Matic Jazz

Case studies Boliden mines economies of scale – Copper/Sweden Pit Vipers beat the chill – Copper/USA Innovation through interaction – Gold/USA Unforgiving ground – Gold/USA Increasing the blast hole diameter at Geita – Gold/Tanzania 97 Going for gold in Guerrero – Gold/Mexico 101 Coal mining in eastern Australia – Coal/Australia 107 Boosting Siberian energy – Coal/Russia

81 85 89 91 95

109 Hidden treasure – Coal/USA 113 Moving mountains – Coal/USA

Product specifications 117 118 119 143 154 160 165 166 168 170 180 183 186 188 196 198 204

Drilling methods guide Specifications guide Blasthole drill rigs Drill rig options Tricone rotary blasthole drilling Bit selection When to change a bit How a rock bit drills Importance of records Air practices Rock formation & drillability Guides for best bit performance DTH hammer specifications Secoroc grinding tools DRILLCare Glossary of terms Where to find us

For latest updates contact your local Atlas Copco Customer Center or refer to www.atlascopco.com/blastholedrills

Produced by: Atlas Copco Drilling Solutions LLC, PO Box 462288, Garland, TX 75046, USA, Phone +1 972 496 7400. Publisher: Ulf Linder, [email protected] Layout: Rafaella Turander, ahrt informationsdesign, Örebro, Sweden, [email protected] Editing team: Ulf Linder, Diane Norwood, Patsy Thomas, Nichole Schoch, Mark Bausch, Gunilla Lindberg, Marino Wallsten, Torbjorn Viberg Adviser: Dustin Penn, [email protected] Contributors: Brian Fox, John Stinson, Dustin Penn, Clarence Zink, Rick Meyer, Leif Larsson, Darwin Hollar, Jeff Rose, Bo Persson, Guy Coyne, Ron Buell, Gunnar Nord, Sverker Hartwig, Jim Langford, Jon Torpy, Stig Fredriksson, all name.surname@country code.atlascopco.com William Hustrulid, Hans Fernberg, Stephen Boyce, Kyran Casteel, Scott Ellenbecker, Kenneth Moffitt, Ewald Kurt, Digital copies of all Atlas Copco reference editions can be ordered from the publisher, address above, or online at www.atlascopco.com/rock. Reproduction of individual articles only by agreement with the publisher. Printed by: Prinfo Welins, Örebro, Sweden. www.welins.se Legal notice © Copyright 2009, Atlas Copco Drilling Solutions LLC, Garland, Texas, USA. All rights reserved.Atlas Copco is committed to comply or exceed all applicable laws, rules and regulations. Photos in this publication may show situations which complies with such laws, rules and regulations in the country where the photo has been taken but not necessarily in other parts of the world. In any case think safety first and always use proper ear, eye, head and other protection to minimize risk of personal injury. This publication, as well as specifications and equipment, is subject to change without notice.


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Foreword “If it can’t be grown, it must be mined.” It is a common saying in our industry, but it bears repeating. As the world population grows, mining must keep up to supply the material needs of people everywhere. Open pit operations continue to account for the majority of mined materials. In their 2008 Mining Project Review, Raw Materials Group (as published in Engineering & Mining Journal) shows open pit methods accounting for over 90 percent of planned capital expenditures for known projects.

product development, technology, production facilities and customer centers around the world. We have established ourselves as a leader in open pit mining with machines running in widely varying operations and conditions across the globe. We’re happy to share some of these case studies and technical articles with you, and anticipate that the information can be put to use to help improve the productivity and reliability of open pit mines everywhere.

Atlas Copco is proud to be part of the open pit mining industry. The rotary and down-the-hole (DTH) blasthole drills and tooling we offer account for only a small part of an open pit mine’s capital and operating cost. However, they play a critical role as they kick off the material movement portion of the mining process with the drilling of blast holes. No matter how powerful shovels, draglines or loaders might be, they can’t dig solid rock.

Going forward, we will continue to aggressively develop new and improved products aimed to safely increase production and minimize operating cost and downtime. We can only do this through interaction with our mining customers. We encourage feedback from the production and maintenance personnel who work with our rigs to help guide our improvements, and hope to be able to share our mutual success stories in future editions of this Blasthole Drilling in Open Pit Mining reference guide.

Since the acquisition of Ingersoll-Rand Drilling Solutions in July 2004, Atlas Copco has made significant investments in

We hope you enjoy this first edition.

Brian Fox Vice President, Marketing Drilling Solutions LLC [email protected]

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Talking Technically

From gunpowder to Pit Viper Drilling and blasting The rotary blasthole drilling rig was a long time coming. Gunpowder was invented in China about 1000 A.D. But in Europe at least it took another 500 years or more before miners started to use it for blasting and a further three centuries for the introduction of mechanized drilling in surface mines. Mobile blasthole drilling rigs have been in use for only some sixty years.

Gunpowder The application of blasting agents apparently began in Hungarian mines sometime during the sixteenth century. To make better use of the explosive force, miners started to place the powder in holes and it is certain that drilling and blasting were used in several German and Scandinavian mines early in the seventeenth century, for instance at the Nasafjäll silver mine in Lappland in 1635, and in 1644 at the Röros mine in Norway. One-man drilling with the help of a drill steel and sledgehammer was the established technology used in the

Drilling with sledgehammer was the established method before the development of the rock drill.


The Pit Viper is designed for production drilling of large holes in hard rock conditions.

eighteenth century. This physically demanding technique evolved only slowly but, despite the mechanization of other industries, remained in quite widespread use until well into the twentieth century. However, powered drills did start to mount a challenge in the 1800’s, the competition in the USA being symbolized by John Henry who in 1870 hammered through 14 feet in 35 minutes while the steam drill only completed nine feet. The first patented rock drilling machine was a steam driven percussion drill invented by J. J. Couch in Philadelphia in 1849 but it may have been preceded by a machine manufactured by the Scottish engineer James Nasmyth ten years earlier. This patent spurred a period of rapid development, accelerated in the 1860s by Nobel’s inventions of the blasting cap and safe dynamite explosives. From 1850 to 1875 some

110 rock drill patents were granted to American inventors and seven for drill carriers while 86 patents were issued in Europe during this period. In 1851 James Fowle, who had worked with Couch, patented a rock drill that could be powered by steam or compressed air and could rotate the drill steel by means of a ratchet wheel controlled by the piston's back-andforth movement. In the 1860’s large scale rock drilling machines were built for tunnelling by engineers in Europe and the United States. One of the most successful of these early rock drills was the second refined version of the Burleigh rock drill, which was put into service in October 1866 at the Hoosac tunnel in Massachusetts. The performance at this tunnel project showed that rock drill development had taken the step from an experimental product to a proven and rather reliable technology. 3

Talking Technically

In 1871, a number of patents were issued to the inventor Simon Ingersoll, who started the Ingersoll Rock Drill Company The machine produced by Ingersoll was at this time regarded as the best rock drill yet produced, and it was followed in the mid 1880s by another success, the famous “Ingersoll Eclipse” machine.

In 1871 the American inventor Simon Ingersoll patented a steam powered rock drill, later to be operated on compressed air. Ingersoll formed the Ingersoll Rock Drill Company in the same year, during the following year purchased the FowleBurleigh patents and also merged with the Burleigh company. The new compact rock drill launched by Ingersoll was a simple and strong design with few moving parts. The designers had kept in view the tough conditions in which the rock drill had to work, and the contemporary technical opinion regarded his new rock drill as the best yet available on the market. During the years to come Ingersoll bought out many small firms and expanded his company. The Ingersoll Rand name came into use in 1905 through the combination of Ingersoll-Sergeant Drill Company and Rand Drill Company. The AB Atlas enterprise had been founded in February 1873 at a time when the Swedish railway net was being rapidly expanded. Three years later, now with 700 employees and the Stockholm shops completed, AB Atlas had delivered more than 600 railway wagons. Diminishing demand from the railroad sector, combined with years of losses, led to a reconstruction in 1890. During the years to follow new product lines were added, including compressed 4

The Ingersoll rockdrill was a simple and strong design with few moving parts.

air tools, compressors, diesel engines and the first Atlas rock drill which was launched in 1905.

Further development The design of the first Atlas rock drill featured an advanced rifle bar rotation but with a weight of 280 kg (617 lb) it was very heavy for manual use. Immediately and for the next 25 years Atlas focused on light weight hand rotated drills like the Cyclop, Rex, and Bob. The real Atlas winner among lightweight hand-held rock drills was the RH-65 from the year 1932. This machine had more efficient shank and chuck designs for better steel guidance

and longer shank life. Used with the new pusher leg feed system developed in the 1930s, the RH 65 was the most important element in what was later to become known as the "Swedish method" of underground drilling. In the United States Ingersoll-Rand expanded into pneumatic tools in 1907 by acquiring the Imperial Pneumatic Tool Company of Athens, Pennsylvania. In 1909 the company bought the A.S. Cameron Steam Pump Works and entered the industrial pump business. Ingersoll Rand also acquired the J. George Leyner Engineering Works Com-pany. This firm had developed a small, pneumatic hammer that could be operated by one man. This “Jackhamer”

The first drill made by Atlas "pneumatic rock drill No. 16" had a weight of 280 kg (617 lb) and was heavy and difficult to handle - at least two men were needed to move it.


Talking Technically

introduced in 1912 became a popular item, and the company progressively developed the design as well as supplying compressors to the expanding construction and mining industries in North and South America

Rock drilling tools The parallel improvement of drill steel quality had started during the 1890s with development of heat treated drill steel that could better resist deformation. But sharpening the tips required extensive haulage of tons of drill steel between drilling sites and the work shops. The detachable drill bit was developed in 1918 by A L Hawkesworth, a foreman at the Anaconda copper mine in Butte, Montana. The first versions used a dovetail joint to the drill steel while later versions were threaded or tapered. The rods were retained at the workings and used with new or re-forged bits. In Europe during the German collapse in 1918 a team was formed at the Osram lamp factory to develop cemented tungsten carbide as a substitute for industrial diamonds. In 1926 the first cemented tungsten carbide became available as a “magical” machine tool for turning and milling operations. Early tests were made in 1928 trying to use tungsten carbide bits for rock drilling in German mines and before World War II promising results were obtained. By this time the research team had scattered and some members had been forced to leave the country. One of these, Hans Herman Wolff, found refuge in Sweden where he worked at the Luma lamp factory. Dr Wolff manufactured a number of bits according to designs provided by Erik Ryd at Atlas. The bits were tested in the Atlas test mine. In 1942 Atlas, Sandvik and Fagersta signed a cooperative agreement and it was not until 1945, after a long improvement process, that the new cemented tungsten carbide drill bits were as economical to use as conventional steel bits. The post-war years saw Atlas achieve further major advances. In 1948 the company introduced an RH 65 upgrade, the RH 656, which was designed to use the new cemented carbide tipped drillsteels.The superior performance of the “Light Swedish Method” was exploited Blasthole Drilling in Open Pit Mining

The US patent for a dual roller cone bit was issued to Howard Hughes Sr. in 1909.

worldwide and culminated in 1962 with the completion of the Mont Blanc tunnel. With development of highly mechanized drill rigs and with the introduction in 1973 of the COP 1038 hydraulic top hammer drill Atlas Copco laid the foundation to become a world leader in top hammer drilling technology. (See article from wagon drill to SmartRig, Surface drilling, Fourth Edition 2008).

rollers equipped with steel teeth. Drilling was accomplished by transferring a pulldown force to drive the teeth into the hole bottom. The three roller cones turned as the drill string was rotated, and the teeth crushed and spalled the rock. While tophammer drills could be used for small blast holes in rock, this method was not suitable for large hole diameters; for these rotary drills were

Rotary bits Rotary drilling with drag bits was the common method used in oil drilling. These bits were suitable when drilling in soft formations like sand or clay but not in rock. The solution for drilling large diameter holes in rock was by using rotary crushing technology instead of trying to cut hard rock with drag bits. The roller cone bit was developed by Hughes and Sharp, and the US patent for a dual roller cone bit was issued to Howard Hughes Sr. in 1909. This new type of bit had two interlocking wheels with steel teeth, and penetrated the rock by crushing and chipping. The success of the new bit led to the founding of the Sharp-Hughes Tool Company, and after Sharp's death in 1912 the name was changed to Hughes Tool Company. The company continued development of the roller cone bit and in 1933 two Hughes engineers invented the tricone bit. This bit had three conical

The Secoroc Tricone bits are now regarded as the ultimate blasthole bit solution.

the best alternative. However, as drillers sought to use the rotary system for progressively harder rock formations so the feed force (pulldown) available had to be increased. Roller cones with long steel teeth were used in softer formations for gouging the formation while roller cones with shorter teeth were used for crushing and spalling harder formations. 5

Talking Technically

Secoroc downhole hammer (DHD), also named Down The Hole hammer (DTH)

A parallel development of the tricone bits made it possible to use these high loads on bits. To extend the life of the bits in hard and abrasive rock the steel teeth were replaced by cemented tungsten carbide inserts. Tungsten carbide inserts have significantly increased the number of blast holes that the roller cone bits are able to drill. Improvements in materials have continued to increase the life of the bearings so the cutting structures can be fully utilized. While the geometry of the roller cone bit is much the same as the original bit patented in 1933, the material and technology currently utilized is cutting edge.

Downhole drilling technology Meanwhile, manual lightweight pneumatic drills had also underpinned the expansion of bench mining in open cut mines and quarries. But in the 1930’s downhole drills (DHDs ) were introduced for drilling deeper holes. The main initial development of this technology took place in Belgium and the United States. Atlas designed a downhole unit in the mid-thirties that was used with

good results in two Swedish limestone quarries until the 1950s but the company then ceased further DHD development, only re-entering the market in 1969 with the COP 4 and COP 6 down-the-hole hammers. In 1955 Ingersoll-Rand introduced a new downhole drill design and started to establish downhole drilling on a truly commercial basis. The Tandematic, which at the time was claimed to provide the highest drilling speed ever attained by a downhole drill, was supplied in two standard sizes – the DHD 275 for 4¾* inch and 5 inch holes and the DHD 1060 for 6 and 6½ inch . This later enabled the company to build drill rigs adapted to be used either for rotary drilling or with downhole hammers. The main difference is that downhole drilling requires more air, and consequently these drill rigs had to be equipped with a larger capacity compressor and a more powerful diesel or electric engine. Downhole drill technology went through rapid change in 1960’s and 70’s. In fairly rapid succession I-R developed the DHD 325 ( their first 6" hammer), DHD 325A, DHD 16, DHD 1060, DHD 1060 A and B models, DHD 360 (all 6"

* 1 inch = 25.4 mm, ** 1 bar = 14.5 psi, *** 1 lb = 0.45 kg

The Quarrymaster from 1948 was equipped with a huge 8" bore drifter.

6

drills) and corresponding larger and smaller models, up to the current line of DHD’s. Probably the most significant change in DHD technology was the advent of the valveless DHD. Drill efficiency and life dramatically improved with the elimination of the flapper valve. Of course higher pressure and volume air from the air compressor advancements produced the performance one sees today. Re-entry to the downhole drill market at 6 bar** in 1969 also enabled Atlas Copco to take advantage of improved air compressors and develop more and more powerful downhole hammers, reaching 18 bar in the early 1980s and more recently 25 bar and 30 bar in the larger current hammer sizes.

Drill rigs The mobilization of rotary and downhole drills was linked to significant post-war changes in rotary drilling technology. Up until then rotary drilling had been used in water well drilling and surface mining using fluid circulation to clean cuttings from the hole. Coal mines were using rotary drilling in soft overburden, removing the cuttings with augers. In the late 1940’s it was realized that air was an effective flushing medium with considerable advantages over water, doing a better cleaning job, protecting the bits and eliminating the difficulties of supplying water. Experience also proved that air flushing improved the penetration rate of rolling cutter bits such as tricone bits and extended their life. By using efficient air flushing to keep the bottom of the drill hole free from cuttings the rock breaking process became more efficient. In 1948, Ingersoll-Rand entered the large-diameter blast hole market by launching the Quarrymaster. It really was not a rotary drill, but a large self Blasthole Drilling in Open Pit Mining

Talking Technically

Rotary table and Kelly bar concept.

propelled mounting in the 40,000 lb weight range, designed with on board air and a long drill tower to drill 6 inch to 8 inch diameter holes for mining and quarry applications. The original Quarrymasters were equipped with a huge 8" bore drifter, know as the QD8. This was a piston drill with the drill steel attached directly to the drifter piston. The blow frequency was in the range of 200-300 blows per minute. The drifter used a large rifle bar rotation system. Achieving decent wear life between the rifle bar and rifle nut was sometimes a problem in tight ground. This was a single pass drill system, hole depth was limited by the tower length. The steel system was a heavy wall tubular product, in the range of 4" OD, and was extremely heavy. Since there was no steel change, the weight didn’t seem to be much of an issue. Quarrymasters were used in some large iron mines in Canada and the Atlantic City Iron Ore Mine in Wyoming. Numerous Quarrymasters were used in the rock excavation for the St Lawrence Seaway in Canada. In the same year also Atlas introduced its first mobile rubber tired drill wagons for top hammer drilling, but these were not equipped with any tramming machinery and were intended for considerably smaller hole diameters. I-R development work with downhole drills in the early 1950’s brought about changes to the drill mounting business. First, the Quarrymaster was equipped with the newly developed QRD rotary head, and this along with the new DHD 325 down hole drill, made for a productive but heavy and bulky package. The Drillmaster design, a somewhat smaller rotary drill, was introduced about 1955. It produced the same performBlasthole Drilling in Open Pit Mining

Big picture; Airpowered DM-3 with a DRD-2 Rotary head from the late 1950's. Inset; Tractor mounted Drillmaster, air powered with a DRD Rotary Head from the early 1950's.

ance as the Quarrymaster in a smaller and less costly package. Upgraded versions of the Drillmaster, the DM-1, DM-2 and DM-3 followed in quick succession. Originally equipped with sliding vane air compressors up to 900 cfm*, all were updated to the screw compressor design. The Drillmaster line was equipped with the DRD and later DRD 2 rotary head to provide drill string rotation. As with the QRD rotary head the DRD was powered by a vane air motor and several steps of gear reduction. All of these drills only used hydraulic power, from an engine driven hydraulic pump off the cam shaft, to operate the jacks, tower raising cylinders, break-out wrench, and dust collector drive motor. Neither rotary head was very useful in supplying straight rotary power for tricone bits, hence the future development of the T-4 and DM-4 with hydraulic powered rotary head for straight rotary drilling. I-R’s first truck drill was called the Trucm package. The drill frame package was mounted on a customer provided truck, often a used Mack truck. However, none of the standard truck designs proved very successful. The normal channel truck frames were not sturdy enough, resulting in many cracked and broken truck

frames. I-R’s answer to this problem was to join hands with Crane Carrier Corp of Tulsa, OK, and mount the drill components and tower directly on an I-beam chassis frame, often used for mounting construction cranes. This product became the TRUCM-3 and the same style mounting carried over to the T-4 and T4W introduced in 1968. A major new stimulus for blasthole drilling rig development generally was the introduction in the 1950’s of millisecond delay blasting. This allowed * 100 cfm = 47.2 l/s

The truck mounted T4BH was introduced in 1968.

7

Talking Technically

* 1 ft = 0.304 m ** 1,000 lbf = 4.44 kN = 453 kilogram-force

The DM50 could use bit loads up to 50,000 lbf and was launched in 1970.

blasters to design multi-hole large volume blasts that could be used for mass production techniques in open cut drill and blast mines. In turn this required the introduction of large, mobile drilling rigs able to drill large diameter holes using tricone bits, as well as the formulation of cheap bulk mining explosives based on ammonium nitrate and nitro-glycerine. These and other developments helped the mining industry to keep the costs of bench drilling substantially unchanged during the 1950s and 1960s, despite increasing wage costs. The Quarrymaster and TRUCM machines were made progressively more self-contained through the 1950s. By the end of the decade the air supply was up to 10 bar and the marketing slogan “Pressure is Productivity” was promoted. The drill rigs and rock drills were sold together to maximize revenue but this did encourage other manufacturers to build competing rock drills.

Hydraulics technology adds to drillers options The similarities between the air requirements of rotary and downhole drilling 8

made the design of rigs able to do both an economically attractive proposition. In 1965-66 Ingersoll-Rand started work on the switch to hydraulic powered rotation for rotary and downhole drilling, launching first the truck-mounted T4W for water well drilling in 1968. In the same year this rig was modified to make a truck-mounted blasthole rig with a 5-rod carousel, the Drillmaster T4BH, which could drill holes of up to 7⅞ inch diameter and was successfully offered for coal mine drilling throughout the 1970s. The designers also used the power unit, tower and other components to create the crawler-mounted Drillmaster DM4 blasthole drilling rig. This machine was designed from the ground up for both rotary and downhole drilling. A 36 ft* high tower incorporated a hydraulically indexed carousel housing seven 25 ft rods. The rotary head featured an axial piston hydraulic motor and single-reduction worm gear for rotation, providing 5.6 kNm of torque and rotation speeds from 0 – 100 rpm. There was a choice of diesel engine or electric motor for the spring mounted f loating power pack and a range of diesel or electric compressors, enabling use of either rotary or downhole drilling with the company’s DHD-15, -16 or -17 downhole drills. The excavator style crawler undercarriage had tracks with 22 inch triple bar grousers driven by hydraulic motor through a planetary gear drive and chain reduction. In the marketplace the DM4 competed with the more powerful electric top drive blasthole drilling rigs. The late 1960s and 1970s saw heavy takeup of the DM4 rig by the Appalachian coal mines in the United States. And the combination of patented rig, drill and drill rod technology was very profitable for Ingersoll-Rand. The use of hydraulic power for rotation and non-drilling functions meant that more air could be made available for rotary and, especially, for downhole drilling. This engendered an “air race” in the late 1960s and 1970s. The independent downhole drill manufacturers were able to build machines that could drill at 130 ft/hour in the 6 – 8 inch diameter hole range – faster than a rotary drill could achieve in this hole size range,

particularly when drilling in harder rock types. The development of screw compressors to supply air for drilling rigs at up to 20.6 bar led to the 1970s introduction of an airend to supply both low pressure and high pressure air. These units were used in portable air compressors and also onboard drilling rigs, where they enabled downhole drills to outperform rotary drills in the 6 - 8½ inch hole sizes in hard rock mines. However, rotary drills were still better for rock compressive strengths up to medium hard limestone. The higher pressures were also very beneficial for water well drilling, in which air pressure must be sufficient to evacuate the ground water pressure from the hole while drilling.

Expansion of the Drillmaster range Significant corporate developments and one major product launch impacted the Ingersoll-Rand drilling business in the mid-1970s. Firstly, in 1973 the company acquired DAMCO (Drill And Manufacturing Company) in Dallas, Texas, who built mechanically driven pre-split drilling machines for quarrying and light coal stripping. These expanded the Drillmaster range down to the 20,000 lbf* bit weight class. The rigs also used the rotary table drive and kelly bar concept, which lightened the tower structure sufficiently to accommodate rod long enough to drill 40 – 50ft holes in a single pass if required. IngersollRand added their own compressors to create the DM20, DM25, DM25-SP (single-pass), DM35 and DM35-SP rotary rig models. Then, in 1975, the company bought the Sanderson Cyclone Drill Company in Ohio, USA, adding 12 models designed for the water well market. The next extension of the size class range came with the launch of the Drillmaster DM50 with 50,000 lbf of weight on the bit. In this machine the diesel engine drove the hydraulic power pack from one end of the crankshaft and the compressor was directly coupled to the other. This concept was also used on the next two drills to be launched. The first one was a new crawler mounted Blasthole Drilling in Open Pit Mining

Talking Technically

rig for rotary or downhole drilling, the DM45 with 45,000lbf weight on bit. This was followed by a conceptually similar top drive rotary or DHD model, the DM30 and a specialized rotary table variant, the DM-35I, which was introduced in the 1980s for drilling underwater in phosphate mines. It featured a dual kelly system that allowed explosives to be charged through the annulus between the outer and inner kelly. The inner kelly would then be removed for blasting. Later the DM 40SPi was developed for drilling and shooting deeper holes.

Development of large blasthole drills Towards the end of the seventies, the company started designing drill rigs more specifically aimed at the base metal mining market, using power pack concepts developed for deephole drilling. So far, neither air-powered nor hydraulic drive rotary nor downhole drills had challenged the electric motor top drive rotary rigs manufactured in the United States for the 12 – 15 inch diameter hole market. These machines by now had very high weights on bit in the range 100,000 – 120,000 lbf, partly due to the weight of the electric motor for the rotary head, but were not suitable for live tower operation. Ingersoll-Rand’s first response was in 1979 with the development of the Drillmaster DM70, able to drill 10 inch diameter holes in metal mines and up to 12½ inch holes at coal mines using 8.6 bar air for rotary drilling. And in 1979 the company launched the DM-H (Drillmaster – Heavy), the first truly modern large blasthole drilling rig to be used for low pressure rotary drilling of 9 7/8 - 12 1/8 inch holes with bit loads up to 90,000 lbf. The DM-H used hydraulics for both drilling and non-drilling functions and featured a hydraulic propel excavator type undercarriage with easily replaceable grouser pads and in-line components on the deck. It was equipped with a rotary screw compressor and a “live” tower with patented angle drilling system. The tower pivot point was flush to the drill deck and within the dust curtain, reducing the length of unsupported drill rod. It was an all-purpose Blasthole Drilling in Open Pit Mining

machine, with a single-pass version added in the mid-1980's. The machine has been upgraded over the years although replaced by the Pit Viper 351 for hard rock applications. At much the same time the company started to offer electric powered versions of the DM 45 and other models if customers wanted them, for instance for use in open pits where the other key equipment was electric powered. However, although these machines had electric motor power packs they retained the hydraulic rotation system. The first electric drill rig was the DM7B delivered to Clarksburg in 1977, followed a year later by the DM100 delivered to Rock Springs. After recovery from the recession of the early 1980’s, Ingersoll-Rand launched a medium range Drillmaster, the DM-M designed for rotary drilling of 9 7/8 inch holes with bit loads up to 60,000 lbf. Three of the first four DM-M's went into operation at Peabody Energy's new Nor th Antelope & Rochelle Mine in the Wyoming Powder River Basin, now one of the two largest coal mines in the world. Now, over 25 years later, the prototype DM-M is still in operation. The machine featured a carriage feed system with wire rope cables, resulting in a lighter tower and lower center of gravity. In 1989 this model was upgraded to the DM-M2 on which maximum bit load was increased to 75,000 lbf and the hole size capability extended up to 10 5/8 inch. Stability was improved as well. In 1990-91 the company intro-duced the DML for multi-pass drilling to 180 ft hole depth. This new model could drill from 6 to 9 7/8 inch (200 – 250 mm) diameter holes in rotary mode, and 6 – 8 7/8 inch using a downhole hammer. Following a development project based on a customer consultation exercise the DM-M3 was launched at MINExpo 1992. Designed primarily for deep drilling of overburden for cast blasting in large coal mines, the first production DM-M3 went into operation in 1993 at Arch Coal's Black Thunder Mine, one of the largest coal mines in the world. For this new model, the designers raised bit load to 90,000 lbf and the hole diameter range up to 12 ¼ inch while a

The DM-H, launched in 1979, could be used with bit loads up to 90,000 lbf (400 kN).

The first Pit Viper 351 was launched in 2000 and used at the Morenci copper mine in Arizona.

Milestones in development Year

Model

Load on bit

1948

Quarrymaster drifter

1955

DM3

30,000 lbf

1968

T4BH

30,000 lbf

1969

DM4

40,000 lbf

1970

DM50

50,000 lbf

1979

DM-H

90,000 lbf

1983

DM-M

60,000 lbf

1990

DML

60,000 lbf

1992

DM-M3

90,000 lbf

2000

PV-351

125,000 lbf

2004

PV-270

75,000 lbf

2008

PV-235

65,000 lbf

9

Talking Technically

The Pit Viper 235 shown at MINExpo 2008.

Big picture: The electric PV-351E at the Boliden Aitik Mine. Inset: The workplace of today with RCS control and automated functions.

new patented cable feed allowed the use of 40 ft long drill rods.

The launch of the Pit Viper Although difficult market conditions restricted investment in the mid-1990’s, during 1997 the company started work on a new generation blasthole drilling rig design. To differentiate this new range from the Drillmaster series, which initially was designed for drilling large holes in coal mining and soft rock, this new series was - from the very beginning - specified and designed for production drilling of large holes in hard rock conditions. The first one out was the Pit Viper 351, which was successfully launched at MINExpo 2000. Weighing 170 tonnes, measuring 53 feet long, and equipped with a CAN-bus control system with seven on-board computers, the new Pit Viper 351 was at that time the largest and most advanced drill rig of its kind. The advanced control system allowed the drill pattern to be transmitted to the drill rig via a radio network, and it also featured production monitoring, rock recognition and a GPS navigation system. 10

A few months after the Minexpo show, in April 2001, the PV-351 was put to work at the Morenci copper mine in Arizona for final testing and evaluation. The mine had a fleet of 16 drill rigs from a variety of manufacturers, so in addition to the new rig being used for drilling in the hard igneous rock conditions, this was an excellent opportunity for benchmarking the PV-351 with the other brands. The application required 12 ¼ inch diameter single pass drilling of 57 ft deep blastholes using up to 90,000 lbf weight on bit (of the 125,000 lbf capacity). The test was successful: the PV-351 drilled some 2.2 million feet by August 2004 at a recorded average rate of 60,000 feet per month and in some months even more than 80,000 feet per month. Later the same year the multi-pass Pit Viper 275 was launched at MINExpo 2004. Based on the experience from the PV-351, combined with customer consultations, a project had been initiated for development of the PV-270 series. These drills were specified for a 75,000 lbf bit load capacity and were featured a similar cable feed system and automatic cable tensioning to that on the larger PV-351. The multipass version PV-275 with a 195ft depth capacity was

delivered for a test in December 2003 at Peabody's Kayenta coal mine in Arizona where it was used for cast blast drilling for removal of the overburden. This first machine is still in use there and, as a result of the good performance, the mine decided to invest in several additional units. One of these is prepared for quick change between a multi-pass and a single-pass tower as an option to be adapted for different applications at the mine. The first mine to use the single pass version, the PV-271, was the Barrick Goldstrike mine near Elko, Nevada. Since the PV-271 arrived at the mine in April 2004 it has been problem-free, and holds an impressive track record with an average penetration rate of 199 ft per hour. The long component life and also the automatic tensioning adjustments for the cables are much appreciated by the mine. Following this tradition of product launches in Las Vegas, the latest addition to the Pit Viper series - the PV-235 - was shown at MINExpo 2008. This is an advanced midrange drill for bit loads up to 65,000 lbf, with the RCS Rig Control System available as an option.

Acknowledgements Editors: Kyran Casteel and Ulf Linder Contributions: Guy Coyne, Ron Buell, Kenneth Moffitt, Brian Fox, John Stinson, Dustin Penn, Gunnar Nord, Sverker Hartwig, Jim Langford, Diane Norwood, Darwin Hollar, Ewald Kurt. Blasthole Drilling in Open Pit Mining

Talking Technically

Ergonomics and safety Machine developments in a new decade Ergonomics today has taken on a broader meaning with the advent of safer work rules, higher work efficiencies and superior design tools. Today engineers can study and design machines that are efficient to operate, maintain, build and transport. Engineering tools, new materials, improved industry standards and new technology allow a designer to model a machine and actually simulate operation under safer operating conditions. During this decade not much has changed with the technical performance of drilling as cutting structures remain the same. Rather the design emphasis has been on efficiency, fewer accidents and ease of operation. Globalization of mining to a higher level is also driving changes. The HIV epidemic in Africa is reducing the workforce at an unheard of rate. New deposits in arctic regions require a new emphasis. This article highlights the advances Atlas Copco Drilling Solutions engineers have made to meet these new challenges.

Ergonomics and safety for operators Today much has changed with regard to operators, machines and machine interfaces. Twenty years ago the industry took a macro view of an operator’s ability to complete a shift without tiring or having an accident. Today designers work to a micro requirement; neither a hand nor a finger must be injured over a 30-year career doing the same function. In the past the requirements were for gauges and levers to be properly placed to avoid human strain during the work shift. Now engineers analyze site paths, a process of ensuring that natural hand motions are used to operate equipment. The drive for safety and efficiency are integrated. Blasthole Drilling in Open Pit Mining

Reference dust management improvement.

Not only does the manufacturer look at drilling as the sole function of an operator. A multi-skilled operator may also manage drilling consumables, complete basic maintenance and report details of bench conditions. These new roles also must be designed into the machine interfaces. Also with regard to improved ergonomics and safety, Drilling Solutions engineers work to design systems that eliminate or reduce the hazards. In the late 1990s when the United States Mining and Safety Administration imposed stricter silica exposure limits for operators, engineers found that improved air quality could not be achieved without removing the concentration levels in certain applications. The drive then became to manage the dust rather than improve air quality through expensive filtration. The goal of Drilling Solutions is to allow the operator to do what comes naturally and to create a work environment that provides superior comfort and safety.

Operator cabins and machine interfaces A rotary drill is recognized as one of two pieces of surface mining equipment that sits and works in its waste, heat and dust. The other piece is the shovel or excavator. The operator’s cabin, or cab, is the device used to protect the operator, a design factor not seriously considered as late as 1995. Nearly everyone would agree today’s automobiles are safer, quieter, offer a smoother drive and are very user friendly. The automobile is becoming the acceptable standard in industry when looking at operator cabins. The visual look of an operator cab has also become a design criteria, as personnel equate past operator cabs with a metal box that induces high fatigue. An automotive’s structure and safety systems keep passengers safe. Likewise today’s drills are engineered to protect an operator against hazards that once injured or killed operators. 11

Talking Technically

allows an operator to watch the areas where visibility is restricted. The combined effect is to give operators a full view from the operator’s chair. The operator chair and flooring play active roles in reducing drilling vibrations, which add to operator fatigue. Now an operator’s chair is often referred to as an operator’s pod, and is adjustable to fit a variety of shapes, sizes and weights. All machine interfaces are now within the operator’s reach. Technology can also play a role in protecting the operator from dangerous work conditions. Drilling Solutions engineers, working with suppliers, are creating a system that allows limits of operation to be defined and to give an operator feedback when an unsafe condition exists. As drilling conditions change within the pit, the machine can be easily reprogrammed to fit the new situation. The result of this combined effort is to deliver a safe, comfortable work environment that is suited for the long shifts required in surface mining.

Operator survived rock fall.

Maintenance ergonomics

The image shows a digital leveling device on which the background can change colors, sound an alarm or remove power when an unsafe angle of operation is experienced.

Comfort combined with ease of operation in one package.

The image shows digital readouts of weight on bit, rotation speed, torque and rate of penetration. It also can be programmed to give an operator visual feedback.

The image above shows a rock fall that the operator survived without injury. Using proper de sign techniques and better materials. Atlas Copco engineers have delivered an operator cab that reduces interior noise levels significantly below the industry benchmark 12

of 80 dBA. For example, the Pit Viper 351 with 1500 hp was measured below 70 dBA when drilling. Like automotive climate control systems are developed to maintain operator comfort more efficiently, today’s systems direct the cooling effort on the operator. The systems are also used to defrost windows in cold weather climates just as automobiles do. Drilling Solutions engineers also are working to advance the cleanliness of the air the operator breathes. Engineers can use computer models to quickly improve line of site. Cabs now feature more window space, which improves visibility, due to glass and insulation technology. Camera technology

Nearly unheard of a decade ago, industry standards now require safe, routine and easy access to all maintenance points. In the 1990s the Australian New South Wales MDG-15 Act gave guidelines for maintenance ergonomics that have become the accepted standard in industry today, and these standards, in addition to factors such as fatigue and safety, drive the machine design effort. For example, Australian studies showed a very high incident rate for personnel getting on and off machines. These results drove the international market to look at alternatives. As a result, placement of key maintenance points could only be in a zone from waist to shoulders, based on measurements for 90 percent of the population. Until fairly recently, operator comfort and safety were only afterthoughts – if they were considered at all. Now, what was once “out of sight, out of mind,” is a critical requirement at the forefront of design innovation.

John Stinson


Talking Technically

An introduction to surface mining The wealth of nations A well-accepted principle is that the wealth of a nation comes from the earth. In the world of mining, a corollary to this is that “If it can’t be grown, it must be mined.” Surface mining techniques are the principal means used to extract minerals from the ear th. The yearly rock production yielding metals, non-metals and coal in the world totals 16.6 billion tons*. Of this, the production from surface mines is about 70% or 11.5 billion tons. Crushed rock, sand and gravel - the fundamental materials required for construction - are largely produced using surface mining techniques. Their yearly production rate totals 23.5 billion tons. To this must be added the materials needed for the production of cement, another 2.3 billion tons. Finally, the amount of waste that must be moved in the process of extracting the valuable materials is estimated at 30 billion tons. Summing, one finds that the total amount of material extracted per year using surface mining techniques is of the order of 67.3 billion tons (Bagherpour et al, 2007). * 1 ton = 907 kg

An increasing demand Today, the population of the world stands at about 6.5 billion people. In simple terms, this means that every year approximately 10 tons of material is extracted using surface mining techniques for every person in the world. If one looks to the future, the UN estimates that in 20 years (2038) the world’s population will have reached about 8.5 billion people. By simply applying the current utilization rate of 10 tons/ person, one would expect the amount of material extracted yearly by surface mining techniques to climb to 85 billion tons. One must keep in mind, however, that today about 95% of the population growth is in the developing countries of the world. Based on their expectations for improved living standards Blasthole Drilling in Open Pit Mining

Photo: Copper mine in the southwest USA.

in the future, the actual estimate of materials mined using surface mining techniques in the year 2038 is 138 billion tons (Bagherpour et al, 2007). The ability of the earth to meet this type of demand is not really a question of resources, since they are clearly there, but rather a matter of price and cost. In looking at the mineral resource base, one must conclude that, in general, the mining conditions will be significantly more difficult than today. In addition, ever-increasing environmental and health and safety conditions are expected to be in place. This means that the entire mining process from prospecting to exploration to development to extraction and finally to reclamation will have to become much more advanced. In many places of the world today, mine closure must be fully and satisfactorily addressed before a surface mine can be opened. This translates into requirements for applying first rate

engineering and technology for meeting today’s requirements and especially those of the future. Atlas Copco is at the forefront in producing the equipment and technologies required today and for addressing the challenges of the future.

A brief synopsis of quarrying and open pit mining This introductory chapter will focus on those surface deposits that require the application of drilling and blasting techniques as part of the overall extraction process. Excluded from the discussion will be strip mining, the mining of sand and gravel deposits and the quarrying of dimension stone. As indicated, large quantities of raw materials are produced in various types of surface operations. Where the product is rock, the operations are known 13

Talking Technically

Financial optimization 1. Capital and operating summation 2. Revenue 3. Cash flow statement 4. Marginal ore utilization 5. Rate of return

Refined ore reserves

Ore reserve analysis

1. Cutoff grade 2. Marginal analysis 3. Design alternatives

1. Break-even analysis 2. Drill-hole evaluation 3. Pit design 4. Marginal analysis

is obtained. By adding the desired production rate into the model a production schedule is generated. Based on the schedule, one determines the required equipment fleet, staffing, etc. to satisfy the schedule. This leads allows one to calculate the capital requirements and the operating costs. With these now-estimated rather than assumed costs, the ore reserves are re-examined and design alternatives evaluated. Eventually, an overall financial evaluation is performed. The double-headed arrows indicate the highly repetitive nature of the process.

Quarries Production scheduling

Equipment and facilities

1. Preproduction costs 2. Working room 3. Stripping ratios 4. Sequencing 5. Reclamation 6. Operating schedules 7. Financial 8. Constraints

1. Capital intensive 2. Equipment selection 3. Operating costs 4. Capital depreciation 5. selective mining

Figure 1. Financial optimization using circular analysis (Dohm, 1979).

as quarries. Where metallic ore or nonmetallic minerals are involved, they are called open pit mines. There are many common parameters both in design and in the choice of equipment. When examining a deposit for potential mining and even when expanding a current operation, one often employs a process called circular analysis. As

shown diagrammatically in Figure 1, the process consists of five components. Although the figure applies specifically for the open pit mining of ore deposits, a similar procedure is followed for quarries. One naturally begins with a description of the deposit and using some assumed costs a preliminary pit design

Figure 2. A diagrammatic representation of a quarry operation.

14

A rather simple but useful definition of a quarry is a factory that converts solid bedrock into crushed stone. Quarries can be either of the common pit type or, in mountainous terrain, the hillside type. Pit type quarries are opened up below the level of surrounding terrain and accessed by means of ramps (Figure 2). The excavation is often split into several benches depending on the minable depth of the deposit. When the terrain is rough and bulldozers cannot provide a flat floor, a top-hammer construction type drill rig can be used to establish the first bench. Once the first bench is prepared, production drilling is preferably carried out using DTH- or COPROD techniques. The excavated rock is crushed, screened, washed and separated into different size fractions, for subsequent sale and use. The amount of fines should be kept to a minimum. Not all types of rock are suitable as raw material for crushed stone. The material must have certain strength and hardness characteristics and the individual pieces should have a defined shape with a rough surface. Igneous rock such as granite and basalt as well as metamorphic rock such as gneiss are well suited for these purposes. Soft sedimentary rock and materials which break into flat, flaky pieces are generally unacceptable. The final products are used as raw material for chemical plants (such as limestone for cement manufacturing, the paper and steel industries), building products, and for concrete aggregates, highway construction, or other civil engineering projects. Blasthole Drilling in Open Pit Mining

Talking Technically

Open pit mines Two major differences between open pit mining and quarries are the geological conditions and the demands placed on the characteristics of the blasted material. For quarries, a majority of the rock products eventually delivered to the customers has only undergone crushing and screening in order to obtain the desired size fractions. An open pit metal mine, on the other hand, attempts to deliver the ore as pure as possible via crushers to a concentrator consisting of mills, separators, flotation and/or biochemical systems, etc. The resulting concentrates/products are eventually sent for further processing before emerging as a final product. For certain metals, this latter process involves smelting and refining. The deposits mined using open pit methods have a variety of sizes, shapes and orientations. Sometimes the distinction between the valuable material and the waste is sharp such as shown in Figure 3 and in other cases the distinction is more subtle - based upon economics. As in quarries, the minerals are extracted using a series of benches. If the orebody does not outcrop, the overlying material must first be stripped away to expose the ore. As the initial pit is deepened, it is widened. The pit geometry is controlled by a number of factors including orebody shape, grade distribution, the stability of the slopes, the need to provide access, operating considerations, etc. For the geometry shown in Figure 3, a significant amount of waste must be removed (stripped) to access the next bench of ore at the pit bottom. Without jeopardizing slope stability, it Blasthole Drilling in Open Pit Mining

Waste Bench slope 72o

Good slope stability o

y

Pit slope 45

Or eb od

Quarries are often run by operators who sell their products to nearby contractors and road administrators. Because the products are generally of relatively low value, they are transport cost sensitive. Hence, wherever possible, quarries are discreetly located as close as feasible to the market. Special measures are required to minimize adverse environmental impacts such as noise from drilling, vibrations from blasting, and dust from crushing and screening to the neighboring areas.

Good fragmentation needed

Figure 3. General principles of open pit mining.

is of prime importance to keep the pit slope angle as steep as possible, thereby keeping the excavated waste to a minimum. There becomes a point where the quality of the material contained in the next “ore” bench is not sufficiently high to pay the costs of the associated waste. At this point in time either the open pit mine closes or, if conditions are

favorable, continuation may proceed using some type of underground method. Figure 4 shows the Aitik copper/gold mine in northern Sweden. It is Europe’s largest copper mine producing 18 Mton of ore per year. Currently at a depth of 480 m it is expected to reach of depth of 800 m before decommissioning. The Bingham Canyon mine in Utah (Figure 5)

Figure 4. The Aitik mine in northern Sweden (www.Boliden.se).

15

Talking Technically

Orebody

Drilling

Overall fragmentation system

Blasting

Loading

Hauling

Mine Mill

Primary crushing

Secondary crushing

Grinding

Further treatment

Figure 5. The Bingham Canyon copper mine near Salt Lake City, Utah, USA. (www.kennecott.com)

has been in production since 1906 and is one of the largest man-made structures in the world, measuring 1200 m

deep and 4400 m across the top. It has produced more copper than any other mine in history and has many

Figure 6. Diagrammatic representation of the overall mine-mill fragmentation system and the mine and mill subsystems (Hustrulid, 1999).

years remaining. With respect to waste removal, the fragmentation demands are simple. Since, the material is not required to pass through a crusher, the maximum size is controlled by the limitations imposed by the equipment used to load and haul the material to the waste dump. On the other hand, good fragmentation of the blasted ore offers great savings in the total costs of the mineral dressing process.

Some forward thinking

Photo: Blasthole drilling of 40 ft (12 m) benches at Newmont's Phoenix mine, Nevada, USA. See page 91.

16

Extraction of the valuable mineral whether in quarries or open pits requires a number of unit operations. Generally, the rock is drilled, blasted, loaded, hauled to a primary crusher and then transported further to a plant of some type for further processing. Figure 6 shows a schematic of the process. Often, mines are organized so that the individual unit operations are separate cost centers. Although there are advantages to this approach, one result, Blasthole Drilling in Open Pit Mining

Talking Technically

Insitu

Drilling Specified Drill Pattern

Drilling

Blasting

Internal environment Minimum wall damage

Blast Engineering

External environment Minimum: Flyrock, noise, airblast, ground vibration

Loading & Haulage

Primary crushing

Secondary crushing

Fragmentation

Conveyor

Loading & Haulage Good: Fragmentation, Pile shape, diggability

Primary crusher

Grinding

Transport

High throughput and bridging preventation

Further treatment

Secondary crushing & grinding Efficient crushing and grinding feed

Figure 7. The mine-mill system represented as fragmentation and transport unit operations (Hustrulid, 1999).

Figure 8. Simplified view of the five different stages of fragmentation, each with a different energy product profile.

unfortunately, can be that the individual managers look at minimizing the cost of their center rather than on the overall objective of overall cost minimization. In reviewing the components in Figure 6, it can be shown that they can be replaced by two operations, fragmentation and transport. In the simplified view shown in Figure 7, there are five different stages of fragmentation each with a different energy – product profile. One must carefully examine the best opportunities for applying fragmentation energy in the various stages on the final product cost. For example, increased fragmentation energy can be relatively easily introduced in the mine by modifying the drill patterns and explosive characteristics. This action may provide an inexpensive alternative to adding the fragmentation energy in the grinding circuit. This process of considering all elements of the fragmentation system, logically dubbed “mine-to-mill” is a recognized part of

mine-mill optimization. In addition to production, there are some other important customers for blast engineering. One is termed the “Internal Environment” and the other the “External Environment.” These are shown in Figure 8. Both for safety and economic reasons, it is important to preserve the integrity of the pit wall. Large diameter blast holes, energetic explosives and wide patterns will be used in the production blasts which will be subsequently loaded out using large excavators and haulage units. Near the pit wall, much more precise techniques involving smaller diameter holes, specially designed explosives, and special timing procedures are employed to minimize wall damage (Figure 9). Unless great care is taken, large loading equipment can easily spoil the results of the trim blasting. The result is that special loading and hauling fleets may be required. Failure to protect the pit walls, translates into the need for flatter slopes


and additional waste removal and/or the loss of reserves. These, in turn, translate into higher overall costs for the mining operation. In carrying out an evaluation of the appropriate drilling and blasting practices, emphasizing mine-to-mill aspects without taking into account the care of the slopes can result in lower production costs but at the sake of higher investment (capital) costs due to greater stripping or lost reserves. Therefore care must be taken to include all the costs when making the analysis. The “external environment” component falls into the category of a potential “show-stopper” since if proper measures are not taken to fully comply with standards, the operation could very well be shut down.

Final remarks Atlas Copco has the advantage of long experience in all types of surface drilling operations, with a product range to match. With its history of innovative 17

Talking Technically

Figure 9. Near the pit wall more precise techniques are employed to minimize wall damage.

engineering, the company tends to think forward, and is able to advise the user on improving design elements of the operation that will result in overall cost savings.

William Hustrulid Hans Fernberg

References

Bagherpour, R., and Tudeshki, H. 2007. Material handling in worldwide surface mines. Aggregates International. Pp 10-14. June. Dohm, G.C., Jr. 1979. Circular analysis – Open pit optimization. Chapter 21 in Open Pit Mine Planning and Design (J.T. Crawford, III and William A. Hustrulid, editors). AIME. Pp 281-310. Hustrulid, William. 1999. Blasting Principles for Open Pit Mining. A.A. Balkema, Rotterdam. Fernberg, Hans 2002, New trends in open pits, Mining and Construction 1-2002

18

Photo: Blasthole drilling and haulage at a mine in the southwest USA.


Talking Technically

Putting rotary drilling into perspective

Atlas Copco’s largest drill, the Pit Viper 351E, operates on a blast pattern at an open pit copper mine. Rotary blasthole drills are the predominant method of drilling 9 inch (229 mm) diameter holes or greater.

Mining prosperity Atlas Copco offers a complete range of rotary as well as DTH and tophammer drill rigs for most types of open pit mining and quarrying applications. But how do these technologies complement each other and how do drillers know which method to choose, and when?

A complete range With the acquisition of IngersollRand’s Drilling Solutions, Baker Hughes Mining Tools (BHMT) and Thiessen Team businesses, Atlas Copco has a complete range of products to offer to large quarries and open pit mines. Much of the world’s mining output begins through drilling of holes with rotary Blasthole Drilling in Open Pit Mining

drills. Ingersoll-Rand built air-powered rotary drills for many years prior to the introduction of their first fully hydraulic unit, the T4, in 1968.

About rotary drills It is important to note that rotary drills are capable of two methods of drilling. The majority of the units operate as pure rotary drills, driving tricone or fixed-type bits. The fixed-type bits, such as claw or drag bits, have no moving parts and cut through rock by shearing it. Thus, these bits are limited to the softest material. The other method utilized by rotary drill rigs is down-thehole (DTH) drilling. High-pressure air compressors are used to provide compressed air through the drillstring to drive the DTH hammer (see illustration page 20). The primary difference between

rotary drilling and other methods is the absence of percussion. In most rotary applications, the preferred bit is the tricone bit. Tricone bits rely on crushing and spalling the rock. This is accomplished through transferring downforce, known as pulldown, to the bit while rotating in order to drive the carbides into the rock as the three cones rotate around their respective axis. Rotation is provided by a hydraulic or electric motor-driven gearbox (called a rotary head) that moves up and down the tower via a feed system. Feed systems utilize cables, chains or rack-andpinion mechanisms driven by hydraulic cylinders, hydraulic motors or electric motors. The preference at Atlas Copco is to use cables for pulldown, as they are lightweight and inexpensive, and allow easier detection of wear to help avoid catastrophic failures. 19

Talking Technically

Pulldown Pulldown is the force generated by the feed system. The actual weight on bit, or bit load, is the pulldown plus any dead weight such as the rotary head, drill rods and cables.

More weight with rotary

The tower supports the drill string during drilling as well as the rotation head and feed system.

Down-The-Hole method

Rotary drilling method TONS

Principle:

The hammer is situated down the hole in direct contact with the drill bit. The hammer piston strikes the drill bit, resulting in an efficient transmission of the impact energy and insignificant power losses with the hole depth. The method is widely used for drilling long holes, not only for blasting, but also for water wells, shallow gas and oil wells, and for geo-thermal wells. In mining it is also developed for sampling using the reverse circulation technique (RC drilling).

20

Principle:

Rotation is provided by a hydraulic or electric motor driven gearbox, called a rotary head, that moves up and down the tower via a feed system, generating the pulldown required to give sufficient weight on the bit. Flushing of drill cuttings between the wall of the hole and the drill rods is normally done with compressed air.

It only takes one look to see that the biggest DTH and tophammer drill rigs are very different than the biggest rotary blasthole rigs. In fact, the Pit Viper 351 rotary drill rig weighs in excess of nine times that of Atlas Copco's largest DTH hammer drill rig, the ROC L8. Yet the Pit Viper 351 is drilling a hole that is generally only twice the diameter. Take a typical medium formation tricone bit with a recommended maximum loading of 900 kg/cm of bit diameter (5000 lb per inch of diameter). With a 200 mm (7-7/8 in) bit, you could run about 18,000 kg (40,000 lb) of weight on the bit. The laws of physics dictate that for every action, there is an equal and opposite reaction, meaning that if you push on the ground with 18,000 kg (40,000 lb), the same force will push back on the unit. There-fore, the weight of the machine must be over 18,000 kg (40,000 lb) at the location of the drill string to avoid the machine “lifting off” the jacks. To achieve a stable platform through proper placement of the tracks and levelling jacks, the distribution of weight results in an overall machine weight that approaches or exceeds twice the bit load rating. This weight does add cost to the machine, but the size of the components also translates to long life. Even smaller rotary blasthole drills are built to run 30,000 hours of operation, and some of the large blasthole drills have clocked over 100,000 hours of use.

Rig design With the exception of one model, the rubber-tire mounted T4BH, Atlas Copco’s rotary blasthole drills are mounted on excavator-style undercarriages. Powerful hydraulic-drive systems allow the machine to tram over a variety of ground conditions, though rotary blasthole drills should always operate on firm, flat benches. Blasthole Drilling in Open Pit Mining

Talking Technically

The drilling platform is supported by a crawler undercarriage except during drilling when it is raised up by hydraulic jacks.

The key component of a rotary blasthole drill is the tower, which is sometimes referred to as the derrick or mast. Atlas Copco towers are four main member, open front structures in which the rotary head slides up and down via a guide system. The length and weight of the tower ultimately dictates the size of the mainframe and undercarriage. Most drilling functions are hydraulically driven. Powering these hydraulic systems, along with the air compressor, is a diesel engine or electric motor. Most rotary drills are diesel powered for good mobility. Electric powered units offer some advantages such as lower power cost (in most areas), no diesel emissions, no refueling requirement and less maintenance. However, some operations are not setup with the proper electrical infrastructure or staffing to run electric units. Even when electric power is available, many customers avoid electric drills as the trailing cable used to provide power makes it harder to move the unit between holes or patterns. Generally, electric power Blasthole Drilling in Open Pit Mining

is preferred on large single-pass units used in major open pit metals mines where electric shovels are employed, though electric power is now available on smaller units such as the Atlas Copco Pit Viper 271, Pit Viper 275 and DML.

The importance of air A key parameter of rotary drilling is flushing the cuttings from the hole. In most rotary blasthole drills, cuttings are lifted between the wall of the hole and the drill rods by compressed air. Sufficient air volume is required to lift these cuttings. Many types of tricone bits have been developed to meet various drilling needs. Softer formation bits are built with long carbides with wide spacing on the face of the bit. This design yields large cuttings which increase drill speed and reduce dust. It is important to have sufficient clearance between the wall of the hole and the drill rods in order for such large cuttings to pass. If this clearance, known as annular area, is not sufficient, the cuttings

The ability to carry long drill rods up to 70 feet provides more time for drilling.

21

Talking Technically

will be ground between the wall of the hole and the rods or by the bit itself (called regrinding) until they are small enough to exit the hole. This results in excess dust and accelerated wear on the bit and drill rod.

Bailing velocity

Rotary drilling with tricone bits is the most cost efficient method for large hole diameters.

To control the dust, the area around the hole is surrounded by a dust hood.

A traditional rule-of-thumb is a minimum of 1,525 m 3/min (5000 cfm) of uphole velocity, the speed at which air exits the hole. The actual amount of air required will vary widely based on the density of the material and the size of the cuttings. Dense cuttings as found in iron ore mines will settle much quicker than lightweight overburden in coal mines and thus need more air coming up the hole to lift them; 1,525 m3/min (5000 cfm) may not be enough. However, harder material is generally drilled with hard formation bits that utilize shorter cutting structures, thus yielding smaller chips. Conversely, some soft material can be drilled effectively with only 915 m 3/min (3000 cfm) uphole velocity. Unfortunately, many operations have tried to increase uphole velocity by increasing the diameter of the drill rod. This is obviously much easier than getting a larger air compressor by retrofitting or purchasing a new machine. In some conditions, this strategy works, but more often, the reduced annular area results in increased wear and dust, and the drill rate may even drop. Whatever the application, it is critical to have proper bailing air.

Dust control

Large diameter holes produced by rotary drills, such as this Pit Viper 275, yield blast patterns with wider burden and spacing, resulting in fewer holes drilled.

22

A necessary evil created by the air compressor in drilling operations is the generation of dust. To control the dust, the area surrounding the hole is enclosed by a dust hood. Dust hoods are sealed on the sides by dust curtains, and where the rod comes through the deck by a rod wiper or dust seal. A dust control system must be used in conjunction with the dust hood and curtains. The two most popular types of dust control are dry dust collectors and water injection. Dust collectors are essentially large vacuum cleaners that pull the dust away from the dust hood and run it through a collection of filter Blasthole Drilling in Open Pit Mining

Talking Technically

Dimension Stone Industry Construction Aggregate Industrial minerals (Cement & Limestone) Gold

1" 25mm

2" 51mm

3" 76mm

4" 102mm

5" 127mm

Coal Copper Iron 6" 152mm

7" 178mm

8" 203mm

9" 229mm

10" 254mm

11" 279mm

12" 305mm

13" 330mm

14" 356mm

15" 381mm

16" 406mm

Pit Viper 351 DM-M3 Pit Viper 275 Pit Viper 271 Pit Viper 235 DML DML-SP DM45 T4BH DM30 DM25-SP 30

ROC L8 ROC L825 CM 785 ROC P65 ROC L7CR ECM 720

ROC L630 CM 765 25

ROC L6 CM 351 CM 348 ROC P55 ROC 203 DTH BVB 25 DTH ROC F6 40

ROC L7 ROC F9CR ROC F9/F9C ECM 660 ROC D9/D9RRC/D9C ROC D7/D7RRC/D7C

Atlas Copco large rotary and DTH drill rigs are included in this book. For information about the range of smaller surface rigs visit www.surfacedrilling.com or contact your Atlas Copco representative

Rotary Rotary / DTH DTH DTH / fully pneumatic

ECM 590/592 ECM 585

COPROD

ECM 580 CM 470

Tophammer

ROC D3 ROC 203

Tophammer / fully pneumatic

BVB 25 ROC T15

Rotary drilling with tricone bits is the most cost efficient method for large hole diameters.

elements. Water injection systems inject a fine amount of water into the air stream. Water injection is the more effective solution for ensuring dust is minimized, but the introduction of water into the hole can slow down the drilling process by increasing the density of the cuttings at the bottom of the hole that the air compressor must move. Water injection systems require frequent refilling of the water tanks, and in freezing conditions, elaborate heating systems must be used. Dust collectors offer a productivity advantage, but they can become plugged if not turned off when wet material is encountered. This is particularly a problem if the wet material freezes in the system.

When rotary is better Every drilling application is different, so we cannot say that there are particular breakpoints where you should transition between drilling methods. Blasthole Drilling in Open Pit Mining

Generally, drilling below 152 mm (6 in) is best accomplished with tophammer units. Above this diameter, it is typically done with a rotary rig, although tophammer units are doing some of this work effectively with the introduction of larger platforms and more powerful rock drills. For harder material, say above 100 MPa (15,000 psi), unconfined compressive strength (UCS), DTH is often faster than pure rotary drilling if provided there is enough air pressure on board. Simply looking at our product range (see above) gives an indication of which methods are commonly used for the different diameters found in construction and mining. There are certain limitations imposed on each method of drilling. With tophammer percussive drills, the power of the rock drill itself limits the ability to transmit adequate force to larger diameter bits, especially at deeper depths when percussive energy is successively reduced with each new rod

connection. Down-the-hole (DTH) tools solve this energy loss problem, but their maximum hole diameter is limited by the volume of air. To build the air pressure that translates directly to impact energy, a certain volume of air is required. Take for example a Secoroc QL80 203 mm (8 in) DTH hammer that is designed to operate at 25 bar (350 psi). Even with our largest high pressure compressor 686 41 m 3/min (1,450 cfm), the pressure will only build to 23 bar (325 psi), thus providing less impact energy. In real terms, each blow of the piston is about 45 kg (100 lb) less than it is designed for. In some cases, this method will still outperform rotary drilling. For most large diameter blasthole drilling, there is simply not enough air on-board for a DTH to be as cost effective as rotary drilling with a tricone bit. Rotary drilling is still the predominant method of drilling 230 mm (9 in) diameter or greater. This is driven primarily by the current limitations of 23

Talking Technically

Total Drilling Cost (TDC) related to bit life and productivity

12000

$6,00

Footage/24 Hours Bit Life (ft) Overall Cost/Ft

$5,00

10000 $4,00 8000 $3,00 6000

4000

299 ft/hour, 1500' bit life High Production

2000

$2,00 218 ft/hour, 5300' bit life Lowest Cost

74 ft/hour, 12,000' bit life Great Bit Life

Productivity versus cost Studies have shown that pure penetration rate will increase linearly with increased pulldown. The same has also 24

$1,00

$-

0

tophammer units and rig air systems. Tricone bits also become more cost effective as the larger bits are equipped with larger bearings which in turn can handle higher loads. These higher loads translate to improved drill rates. Another advantage of rotary rigs is the length of the drill rods that can be carried on board. Longer rods mean fewer connections. Smaller rotary blasthole machines utilize 9.1 meter (30 ft) length rods, while larger units are capable of running 10.7 meter (35 ft) or 12.2 meter (40 ft) rods. By comparison, tophammer or DTH crawler drills use drill steel that is generally 6.1 meters (20 ft) or less in length. Further, some rotary rigs are large enough to handle a long tower that enables drilling of the entire bench height in a single-pass. At the largest open pit mines, rotary units are drilling 20 m (65 ft) deep holes in a single-pass to match the bench heights dictated by the large electric shovels that can dig a 17 m (55 ft) bench.

Total Drilling Cost/Foot

Footage/24 Hours & Average Bit Life

14000

been said of rotation speed. So why doesn’t every operation use more of each? Unfortunately, higher pulldown and rpm usually results in increased vibration and lower bit life. The vibration causes increased wear-and-tear on the rig, but more importantly, it creates a very unpleasant environment for the operator. What invariably happens is that the operator reduces the weight or rpm until the vibration returns to a comfortable level. Some operations limit bit load and rpm even if there is no vibration in order to improve bit life. This is often the wrong strategy as the overall drilling cost per unit, also known as Total Drilling Cost (TDC), should be considered. TDC is calculated using the bit cost per meter/foot and the total rig cost per hour. The unit cost per hour includes labor, maintenance and power, and possibly capital cost. The drilling speed really doesn’t impact this cost-per-hour figure. What it does impact though is the cost per unit produced (cost/meter/foot, cost/ton, etc…). You generally want to push the rig harder to reduce the cost/foot, but there will be a point where the rig overloads the bits (see diagram).

Large versus small There are some drawbacks to rotary rigs. Smaller crawler rigs are more flexible with many advantages such as articulating and extendable booms and guides that allow drilling at many different angles. Unlike crawler rigs, the components on rotary rigs are often not enclosed. They are mounted onto the frame in an open layout that makes them extremely easy to service. Large electric units normally have a machinery house to protect the electrical drive components, and newer midrange sized blasthole units such as the Pit Viper 235 have the option of a machine enclosure. The general trend for 165 mm (6-1/2 in) or less is towards the smaller, more flexible units. However, many large scale quarries and small mines still favor the durability, life and simplicity of the larger rotary rigs for these small diameters. For the large scale open pit operations that yield a high percentage of the total worldwide mineral production, it is anticipated that rotary drilling will remain the primary method for years to come.

Brian Fox Blasthole Drilling in Open Pit Mining

Talking Technically

Automated surface blasthole drilling The current series of Atlas Copco Pit Viper drill rigs is based on the latest, well proven computer and information technology. These drill rigs are of modularized design in both hardware and software, so upgrades of the latest technology are available for older models. Se- veral options are available to facilitate quality drilling. Atlas Copco has applied the same new automation technology for other underground drilling equipment such as Simba production drill rigs, Boltec rockbolting rigs, and ROC surface crawler rigs. For the customer, this means commonality of components and training, leading to a better understanding of both the capability and the maintenance of Atlas Copco products. For the company, it allows continuous product development, which can be applied straight across the range.

A HOLMBERG 2007

Utilizing the technology platform

PC-card

CCI module

AP module

Resolver module

I/O module

Atlas Copco's Technology Platform.

Introduction Atlas Copco has introduced a number of new drill rigs for the Drilling Solutions Division using a common technology platform. This approach allows development of new functionalities for the drill rigs, which experience has shown in both underground drilling and haulage as well as surface drilling. The current generation of machines is designed for high productivity, quality drilling and a comfortable working environment for the operator. Drilling a hole constitutes a small amount of the direct cost and time of mining, but has a major impact on the other production processes because it affects fragmentation, backbreak, underbreak, wall control, loading, haulage and processing. Although great attention is paid to penetration rate and wear of drill steel and bits, Atlas Copco is also interested in what drilling can do to improve rock excavation overall. The inputs to this ongoing process come from customers and from research projects where new technology is applied to drilling operations. Blasthole Drilling in Open Pit Mining

PV-275 cabin with RCS provides an excellent operator´s environment and improved drilling performance.

25

Talking Technically

RCS cabin on a PV-351.

The control system replaces the electric/hydraulic joystick and console layout pictured here.

Rig Control System

surface blasthole machines, the flexibility of the system is highly utilized and can be adapted and configured for all different types of products. Customers can start at a low level of automation and, as their requirements change, can upgrade. New functionality can be added without major rebuilding of the machines.

The automation platform for Atlas Copco blasthole drilling equipment is the Rig Control System (RCS), which is based on standard PC-computer technology. The new generation of RCS rigs has taken a quantum leap forward with respect to logging capabilities, serviceability and drilling accuracy. CAN-bus technology provides the backbone of this new rig control system. It is flexible and easily expandable, allowing new units to be added anywhere along the data bus by cable. The electronic modules are all developed solely for the RCS rigs, and are ruggedized and protected from external magnetic and electric influences. For

RCS cabin on a PV-270 series.

26

Common automation All Pit Vipers can be equipped with RCS Basic, which provides a number of safety and interlock features and a series of options– Autolevel, Autodrilling, GPS hole navigation, Rig Remote Access (RRA) and communication, wireless remote tramming, Measure While Drilling

(MWD) data log files, and International Rock Excavation Data Exchange System (IREDES).

Safety features The RCS Basic provides the machine with additional standard interlocks compared to the electric-over-hydraulic machines. A few of the interlocks created with the software are: • Hole depth indicator – displays the rotary head position as well as the depth of the hole drilled; • Pipe in hole tram interlock – rotary head must be in a safe position to allow tramming; • Jack interlock – pipe in the hole will disable jack functions to protect the machine and reduce bending of rods; • Rod support interlock – prevents damage of the rotary head and rod support by not allowing feed with rod support not in the stowed position; • Carousel no-bump – prevents damage to the carousel by limiting pulldown pressure with the carousel not in the stowed position; • Breakout wrench protection – prevents damage to the breakout wrench by disabling pulldown with wrench not in the stowed position; • Engine and electric motor information displayed over the touch screen maintenance screens; • Low fuel, lube and water level messages; and • Tram interlocks, so a trigger must be activated to allow tram function. Blasthole Drilling in Open Pit Mining

Talking Technically

On the panel 1. Auto interlock button. Press and hold this first and then choose one of the following auto functions. 2. Using multilever rocker switch. Autolevels up for switch up. Autodelevels for down in drill mode. 3. Autodrill. Drills to predefined depth and returns head to propel safe position. Anti-jam, void detection and so on in drill mode. 4. Future option. Auto tramming or autonomous operation. RCS Automated Function Buttons.

Autolevel/Autodelevel To increase the quality in setup of the drill, leveling the machine on the jacks is performed automatically. This will help an average operator to close the gap to the skill level of an expert operator. Installation of this feature will reduce wear and tear on the machine structure by limiting torsional effect on the mainframe and tower while leveling. This function's performance, of course, depends on ground conditions, but for a normal bench flatness, the results are that leveling is done in less than 35 seconds with an accuracy in pitch and roll to 0.2 degrees. Well

structured and integrated fault handling is vital for Autolevel/Autodelevel. This is to avoid unwanted tip over of the drill in case of uneven ground conditions or internal component faults.

Autodrilling In many cases there are several types of rock conditions within one blasthole, and an operator must be alert at all times to react to these varying ground conditions. With Autodrilling, computers are now the operators reacting to feedback from the machine’s gauges. Atlas Copco's autodrill feature has reproduced the expert operator's reactions into an automatic drill control. When activated, this function will detect the rock when the bit touches the ground, and start your air, water, rotation and feed to collar the hole. After the collared distance has been met, then this module will adjust air, water, rotation and feed to a drilling setting. This feature will apply optimal pulldown and rotation to try and drill as fast as possible without stalling the rotation or getting stuck. Once the target depth has been hit, the autodrill feature will clean the hole or flush the hole, shut off the air and water and then return the bit to a tramming-safe position. This feature provides the consistency of drilling to the correct hole depth, and a consistent water flow to maintain the hole so it does not collapse. Currently this is available for single-pass drilling and multi-pass drilling, although a manual rod change must be made at this time.

GPS navigation screen.

Drill dashboard - drilling screen.

Leveling screen.

Settings screen.

Autodrill diagram

Hole building

Start

Rock contact detection

Collaring

Drilling

Hole cleaning

Finished

Anti-jamming / vibration control

This diagram is valid for a single-pass drill. For multi-pass drills a rod handling system sequence is added to the Autodrill sequence, which is currently not developed for rotary drills.


27

Talking Technically

Remote Rig Access and communication .

GPS hole navigation To ensure the blasthole is precisely positioned where the mine engineer has designed the blast pattern and is drilled to the correct depth, GPS hole navigation has been developed for the RCS platform. This hole navigation system uses antennas mounted on the tower rest and radio antennas on the cab to produce an accurate bit position. Drill plans designed with the local mine coordinates are imported to the system, and the bit position is provided in real time. The bit position is very accurate and is calculated by taking into consideration the variability on the bench, providing the operator with the correct depth to drill each specific hole. This feature also provides a moving map display with zoom functions as the rig is trammed closer to the desired blasthole location. The dominant system for positioning of a rotary drill on a blasthole drill plan is with satellite navigation based on GPS or GPS and Glonass. Accuracies up to ±10 cm are possible to reach depending on installation and number of available satellites. The integration of the GPS receiver to the control system is via a standard RS serial link. Protocol used is preferably the standardized NMEA0183. The advantage of having the GPS system as a positioning sensor enables customers to choose products of any brand (Trimble, Leica, Topcon) depending on the preferred standard in the actual mine. 28

Wireless remote control, compact portable package.

Rig Remote Access and communication The Rig Remote Access (RRA) system from Atlas Copco gives a customer the ability to connect the drill rigs to a standard computer network on a work site. The RRA system allows access information on the drill rigs from any authorized point in a network. The RRA system basically consists of a communication server onboard the drill rig and a network adapter. The server supplies the user with three functions: a web server that can connect to any standard web browser, an FTP server to enable transferring of data (files) to and from the drill rig, and a server process that enables any data to be integrated into the user's administrative systems. If a commercially available "office" network is used on the work site, which is easy to install into the existing infrastructure, it restricts the RRA functionality to only remote access, and does not permit remote control. Standard communication equipment is also used that makes the RRA easy to upgrade and adapt to new and more effective equipment when available. The system also utilizes standard communication protocols such as PPP or TCP/IP. With a wireless network connection to the drill rig, a number of working procedures in the mine are simplified and several new features are available to the mine planning organization. The basic mine planning and control functions can be

simplified substantially by having a direct link to the machines. Advanced work orders that previously were distributed at the beginning of each shift can now be distributed instantly. This leads to a more flexible and adaptable production organization. Computer designed drill plans and work orders that earlier had to be loaded manually with a PC card can now be downloaded directly from the office computer where they were created. This saves time and personnel and also allows last minute changes in order to adapt to variations in geology and ore geometry. Log files generated during drilling, also previously transferred from the rig with a PC-card, can now be collected from any computer connected to the network. This means that information carried by the log files, e.g. production data, geological and geomechanical data (strata recognition) is available for the entire organization as soon as the drill completes its hole/pattern. Manual shift reports stating number of holes, drilled depth, etc. can now be completed automatically from data logs without human involvement. RRA is also a tool for more advanced service and maintenance procedures. The operation of the rig can be followed remotely and monitoring of drill rig status can be made online using a standard web browser on a remote PC. “Web pages” are set up similar to the native RCS display on the rig. Troubleshooting can be done remotely using the built-in menus in the Blasthole Drilling in Open Pit Mining

Talking Technically

RCS system. This can also be done by specialized technicians and engineers at Atlas Copco's product companies. Furthermore, entire replacement of the RCS software has been done remotely from Örebro, the Rocktec office. The RRA system has been introduced to a number of underground mines and construction sites since 2003, which has eased implementation in surface mining operations.

Wireless remote tramming The wireless remote tramming function allows the operator to tram a Pit Viper from the bench within a 60-meter distance. This will allow an operator to walk all the way around the machine and tram the rig to avoid any blind spots or next to a highwall or berm to prevent damage to the machine. This controller is also equipped with safety triggers, so the operator must have control of the unit with his hands to tram the machine. The function has an emergency stop button and engine speed control as well, and can be equipped with additional functions when available.

IREDES The data that is transmitted to and from a drill rig or any other mining equipment is arranged in a specific format. Often different equipment suppliers use their own specific format, allowing data communication only between their own equipment. For a mining company or a contractor, an industry standard will simplify integration of equipment from different suppliers. Atlas Copco was one of the originators of the International Rock Excavation Data Exchange Standard (IREDES) initiative in 2000. A positive and open attitude between the IREDES members has led to data profiles for the different processes in the rock excavation process – drilling, loading and blasting. Atlas Copco is fully committed to the IREDES standard and the rotary drilling product line is IREDES compliant.

Measure While Drilling Measure While Drilling (MWD), strata logging, logs several drill parameters Blasthole Drilling in Open Pit Mining

Teleremote office installation.

during production drilling, and the data can be used for prediction of geological and geochemical variations within drill patterns on a bench. This can help determine the strength of that specific rock type. A rock mass is also intersected by fractures and faults that strongly influence the conditions of the rock mass and, therefore, engineering aspects such as charging and blasting of the drill pattern. This data, when integrated with the blasting plan, should influence the explosive charging and specific density applied throughout the pattern, which will in turn influence the loading, hauling and processing of the ore.

Teleremote operation This feature uses the mine's wireless network, either 2.4 or 5.2 GHz frequency, and allows an operator to utilize the machine functions from a remote location including, drilling leveling, tramming, and GPS hole navigation. A dedicated communication channel that guarantees bandwidth and latency times for real time control of the drill is required. The package can be equipped with a four-camera system that is compressed to limit bandwidth for viewing of the machine from remote locations. This module also includes a dedicated safety system independent of the RCS package. If communication is lost between the remote station and the machine, then it will shut down. Additional safety systems like personnel detection

systems or systems detecting when people enter the working area should be combined with the mine's specific safety instructions.

Autotramming Autotramming is a feature in the development stages and has been tested on a machine at the Garland, Texas, factory. This component utilizes the GPS hole navigation system or can be deployed with an augmented GPS using the standard NMEA string to tram a machine between holes on a blasthole pattern. This pattern is interpreted by the path planner, which is in communication with the drill regarding direction and track speed to tram the machine at an ideal speed to the exact location. This module can reduce wear and tear on the machine structures as well as undercarriage by reducing spot turning and planning a correct path to the next hole. The current requirement for this feature is a "flat" bench, which must be verified by a mine engineer, to allow this machine to stay within its limits. A combination of any or all of these features are available for deployment to fulfill a specific mine's needs for automation. Additional feedback will be required in the future to further enhance the automation package, but the RCS is Atlas Copco Drilling Solutions' platform for automation.

Dustin Penn 29

Talking Technically

30


Talking Technically

Tricone rotary blasthole drilling Rotary tricone bit elements Rotary tricone bits consist of several basic parts: Three “roller cones” with the bit ‘cutting structure’ (tungsten carbide inserts or milled steel teeth) on their external surfaces; “bearing races” machined inside each “cone bore”; three sets of bearing elements consisting of small “inner” rollers, ball bearings, and large “outer” rollers; and three “lugs”, each having inner, ball, and outer bearing races that match the cone bore races and hold the different bearing elements.

Rotary tricone bit fundamentals Rotary tricone bits consist of several basic parts: • Three “roller cones” that hold the cutting structure on their external surface, and the bearings in their interior • The “cutting structure” consisting of either Tungsten Carbide Insert teeth, or milled steel teeth. • Three “lugs”, each of which has the bearing “journals” which match up with the cone bearing “bore”. • Inner and outer roller bearing elements. • Ball bearing elements. These basic parts are then assembled into bit thirds, and three ‘thirds’ are then assembled into a “tricone” (three cone) bit. Once completely assembled into a finished bit, the bit “pin connection” is threaded with the appropriate connection size and type for the bit diameter. The figure at right illustrates the assembled components of a tricone bit and presents a ‘cut away’ of one lug/ cone assembly to show the internal component arrangement. Note that this figure shows air passages from the bit interior into the bit bearing areas. This is an “air bearing” Blasthole Drilling in Open Pit Mining

Elements of a rock bit.

bit. Other types of bearing configurations are “open” (or fluid) bearing, and “sealed” bearing. “Open” bearings do not have any internal air passages, and the back of the cones are ‘open’ to the external drilling environment. “Sealed” bearings are completely enclosed, with no internal air passages. The bearings are sealed off from the external drilling environment, and are filled with pressurized grease.

Rock breakage Contrary to popular opinion, rotary tricone bits do not drill by “crushing” rock. Instead, they actually drill by a mechanism called “spalling”. A European gentleman named Hertz originally defined this method of rock breakage back in the 1880’s. If a force is applied to an “indenter” in contact with a rock

surface, stress fields are set up under that indenter. As the loading force on the indenter is increased, the stress fields extend outward and downward from the point of contact and loading. The applied load creates fractures (cracks) that propogate along the stress field vectors, seeking a “free surface”. When these stress vectors find the free surface, the crack is completed, and the rock above the stress vector breaks free. A rock “chip” or “cutting” is created, and must now be removed. Because tricone bits apply this force to several inserts simultaneously on each cone, the cones must constantly be rotated to new “indenting” positions in order to advance the hole. It would do no good to simply continue to apply weight to the bit without rotation. Nothing would happen. The bit must be rotated to bring new teeth into position for loading and rock breakage. 31

Talking Technically

Drillhole cleaning / cuttings evacuation

Air circulation through nozzles and bearings.

32

Once the “cuttings” are created, they must be evacuated. If the cuttings are not removed from the hole, the bit will be ‘eroded’ by the abrasiveness of the rock chips, and the teeth will quickly wear down and/or fall out, rendering the bit ineffective. In blasthole drilling, hole cleaning is done with compressed air. The rotary bit is either attached directly to the “drill pipe”, or one of a number of other drilling accessories, (bit adaptor subs, bit stabilizers) are used to attach the rotary bit to the drill pipe. The exact attachment method depends upon the drilling situation. In any case, a large volume of compressed air is directed down through the drill pipe (also called the drill string) into the bit. The flow of compressed air is intentionally restricted at the tricone bit by the use of “jet nozzles”, in order to create ‘back pressure” and a “pressure drop” through the bit. This ‘back pressure” forces air into the bearings of an “air bearing” bit, to keep the bearings cool and clean, and to prevent contamination from entering the bit. Secoroc wants to achieve an actual pressure inside the bit of 45 psi (3.1 bar) or higher. This will direct from 15% to 25% of the air into the bearings for bearing maintenance, while the remaining majority of the air creates a “jet blast” against the face of the hole to blow newly formed cuttings away from the bit. The following figure shows the bit’s internal air path in yellow. Jet nozzles are shown in purple. Rock density (specific gravity) varies greatly, depending on what material is being drilled. Coal for instance has a SG of around 1.6, while some iron ores have a SG greater than 3.8. Most rock we drill has an in situ SG of between 2.4 and 2.8. If there is a lot of natural ground water, this can wet the cuttings, increasing the cuttings SG by about 0.1 SG. Secoroc recommends a minimum air “Bailing Velocity” of 5,000 - 7,000 feet/minute (1524 - 2134 meters/minute) for light and dry materials, and 7,000 9,000 feet/minute (2134 - 2744 meters/ minute) for rock materials that are wet or have a high density.

Drilling parameters Secoroc tricone bits generally conform to the IADC rock type classifications. IADC is the International Association of Drilling Contractors, who set many “standards” and “conventions” for the general drilling industry. Secoroc has adapted certain IADC concepts to its tricone bits. Tungsten Carbide Insert bits fall into five IADC classes: • 4-1 to 4-4 - very soft to soft • 5-1 to 5-4 - soft to medium • 6-1 to 6-4 - medium to medium hard • 7-1 to 7-4 - hard to very hard • 8-1 to 8-4 - very hard to extremely hard In general, decades of bit manufacturing, and product development and application experience gives us the following operating guidelines: For 4-1 to 4-4 IADC type bits: • 50 to 150 RPM • 1000 to 5000 pounds of applied load per inch of bit diameter For 5-1 to 5-4 IADC type bits: • 50 to 150 RPM • 3,000 to 6,500 pounds of applied load per inch of bit diameter For 6-1 to 6-4 IADC type bits: • 50 to 120 RPM • 4,000 to 7,000 pounds of applied load per inch of bit diameter For 7-1 to 7-4 IADC type bits: • 50 to 90 RPM • 4,000 - 8,000 pounds of applied load per inch of bit diameter For 8-1 to 8-3 IADC type bits: • 40 to 80 RPM • 6,000 - 9,000 pounds of applied load per inch of bit diameter As the rock gets harder, it is adviseable to apply slower RPM. As more load is applied to a bit it is adviseable to apply slower RPM. “Strong” rocks may need ‘time’ for the indenting teeth to create sufficient stress in the rock fabric to cause it to crack, and the crack propagate. Thus, in ‘strong’ or ‘hard’ rock it is suggested that lower RPM is used. “Weak” rock does not need as much time to react to the indenting teeth. Higher RPM can be used effectively in “softer” ground. These are general guidelines, and are intended as suggestions only. Every rock type is different, and every specific Blasthole Drilling in Open Pit Mining

Talking Technically

IADC vs. Rock UCS 48000

8-1 to 8-4

70000

IADC Class

36000

7-1 to 7-4

56000

22000

6-1 to 6-4

42000

6000

5-1 to 5-4

28000

1000

4-1 to 4-4

10000

0

10000

20000

30000

40000

50000

60000

70000

Rock UCS (PSI)

IADC vs. Rock UCS Chart showing comparison of IADC classifications to rock hardness.

rock type exhibits a wide variation in mechanical properties at an individual site. Individual mines should determine optimum operating parameters for each rock type and drill type at that specific site.

The value of a bit What is the “value” of a bit? What determines how ‘good’ a bit is? Ask around, and you will probably get one of these four answers to the question of ‘value’: • Low price • Long service life • High penetration rate • Low operating cost Secoroc believes the highest “value” a tricone rock bit can have is “low operating

cost”. Considering that the cost of owning and operating a modern rotary drill rig can approach US$400 or more, bit performance needs to be judged on what the total cost of operating the drill is. This then, goes hand in hand with a high penetration rate, and is accompanied by a ‘good’ service life. Consider this example: • Drill operating cost per hour = US$300 • Penetration rate of Competitors bits = 30 meters/hour • Penetration rate of Secoroc bits = 45 meters/hour • Hole depth = 15 meters The “Operating Cost per Meter” is calculated by: • OC/m = Drill Operating Cost / Penetration Rate

Performance comparison for distance, of two bit types, over time.


Thus, it is easy to see that for a 15 meter drilled depth hole: • Competitors Operating Cost / meter is US$300 / 30 = US$10.00 • Secorocs Operating Cost / meter is US$300 / 45 = US$6.66 The faster drilling Secoroc bit saves the mining company US$3.37 for every meter drilled. That is value.

Bit record keeping Without keeping track of bit performance, there can be no way to measure one bit type against another, and one bit supplier against their competition. Secoroc can provide the templates for two types of “Bit Record Book” to record bit performance. Compilation of product performance histories creates a valuable tool for the sales person and bit manufacturer. Different bits can be compared at a minesite. Performance of the same bit at different minesites can be compared. How does one drill type compare against another drill type? If a new mine is being opened, you need to have an idea of what products to offer, and what performance can be expected. Secoroc has a global product performance database available in Lotus Notes. Product performance from mines around the world can be compared. Sales people easily generate a variety of reports for their monthly business reviews and sales calls. Below is an example of a report generated by Perform v6, for two bit types compared over a five month period:

Clarence Zink 33

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34


Talking Technically

Optimizing the rotary drill string Money in the bank In rotary drilling, the careful selection of every drill string component is vital to achieve accurate holes, optimal rock fragmentation and operational efficiency – parameters which affect total operational costs.

Close attention When developing a rotary drilling system, most of the attention is usually given to the drill rig, the capital equipment that requires significant investment and hence a planned payback. The second priority in the system tends to be choice of rotary tricone drill bit – the Tricone. However, to utilize the full power and capacity of the rig and the bit, and at the same time increase service life and productivity, consideration should also be given to the entire drill string. The optimal drill string includes a shock absorber at the top, a rotary deck bushing to centralize the drill string as it passes through the deck of the rig, strong and straight drill pipes and finally a hole stabilizing roller stabili-zer or bit sub-adaptor to optimize the performance. Giving the necessary attention to every part of the drill string will lead to the lowest total operating costs in rock excavation and fragmentation.

The rotary drill string The primary purpose of the drill string is to transmit the rotational torque and weight from the power source – the rotary head of the rig – to the rock breaking drill bit. As for every rock drilling method, the power must be transmitted as efficiently as possible, and return as few vibrations as possible, as these cause unnecessary wear on the rig and reduce penetration rates. When selecting components for the drill string, attention must be given to the different roles of the support tools in the string. The aim can be to: Blasthole Drilling in Open Pit Mining

Giving the necessary attention to the drill string components will pave the way for quality drilling and lower total operating costs.

• reduce wear and tear on the drill rig • absorb damaging vibrations travelling back up the drill string • improve transmission of energy from the rotary head to drill bit • centralize the drill bit within the hole • longer bit life • reduce friction as the drill string passes through the drill rig deck • stabilize the hole wall to prevent hole caving • increase penetration rates and lower drilling costs • achieve blast hole accuracy for improved blasting efficiency • improve the end result – the fragmentation of the blasted rock.

Shock absorber At the very top of the drill string – between the rotary head and drill pipe – a shock absorber is commonly used. As the name indicates, the intention of this tool is to reduce the negative effects of harmful vibrations that travel back up the string as a result of the drilling process. The benefits of using a shock absorber include: • improved torque control • increased drilling penetration rates • better drill rig availability and extended drill rig drive head and mast life • longer service life of drill bits 35

Talking Technically

Smoothdrive™ shock absorbing sub

Square drive flange method

Welded strap method

Smoothdrill™ shock absorbing sub

B A D C E

Threadsaver sub

Full length repairable Teamalloy™ body drill pipe (box-box optional)

OD ID

Centeroll™ rotary deck bushing (repairable)

WLS

EZ-Drill™ roller stabilizer

Duralloy™ bit sub adaptor Duralloyª bit sub

Secoroc Tricone bits

The optimal drill string includes a shock absorber, a rotary deck bushing, strong and straight drill pipes and finally a hole stabilizing roller or bit sub-adaptor.

Deck bushing To guide the drill string and reduce the risk of wobbling, a rotary deck bushing is utilized at the drill rig deck opening. The deck bushing guides the pipes to prevent reduction of rotary head torque and assists with the final straightness of the hole. The deck bushing contains an outer housing with a top flange that allows it to fit perfectly into the deck opening. A series of roller bearings allow the inner sleeve to rotate with the drill string. Wear of the deck bushing occurs primarily on the inner sleeve as cuttings are blown upwards, between the drill pipe and the inner sleeve.

while still achieving an acceptable life of the Tricone bit. The use of a strong and straight alloy drill pipe is one of the best ways of preventing wobbling of the drill string and hole deviation. Drill pipe is subjected to a severe and abrasive environment, due to the rapid evacuation of drilling cuttings through the annulus of the hole, causing a sandblasting effect on the drill pipes. It is logical, therefore, to utilize only the best alloy steel for both the threaded connections and the body of the drill pipe. Special wear protection material is applied to the most critical areas of erosion at the bottom of the drill pipe. The drill pipes can, in most cases, be refurbished to prolong service life.

Drill pipe

Bit sub adaptor or stabilizer

The role of the drill pipe is to transfer sufficient amounts of rotational torque and weight to the drill bit. The goal is to establish an optimal rate of penetration

To connect the bit to the drill pipe, a wearprotected bit sub adaptor is generally used when the rock formation is relatively competent, and not in need

36

of stabilization within the hole. In some softer, fractured rock formations, it is worthwhile to consider the use of a stabilizer as an alternative. The roller stabilizer contains three roller assemblies which provide support against the hole walls, serving to both guide the drill bit in a straight direction and pack the wall of the hole to prevent caving in. The use of either straight or spiral-bladed stabilizers is strongly discouraged as this causes excessive friction when these blades are at full gauge diameter, while they also lose gauge diameter rapidly rendering them virtually useless as a stabilizer after only a few shifts. In addition, the spiral-bladed stabilizer slows down the evacuation of the cuttings. So, to achieve improved hole straightness, hole wall integrity, and at the same time increase the effective life of the stabilizer, only stabilizers with rollers fitted with cemented carbide inserts are recommended. All in all, when you consider the significant amount of capital invested in a rotary blasthole drill rig and the annual investments in Tricone drill bits, the selection of the best quality rotary drill string tools that are suited to the application, is critical to the eventual success of the drilling program. The rotary drill string tools should not just be considered as mere support tools, but rather as an essential, integrated part of the total rotary drilling system. The following basic criteria should be considered when deciding which rotary drill string tools will best optimize overall drilling performance and cost effectiveness: • are quality materials and innovative design used to address specific drilling problems? • can the tools be refurbished for an economical second run? • does the supplier of the tools offer application and follow-up service? In conclusion, straight blast holes drilled exactly to the pre-planned hole bottom positions, pave the way for lower total operating costs, taking into account the entire process – drilling, blasting, secondary breaking, loading, haulage and crushing/screening.

Rick Meyer


Talking Technically

Increased productivity with DTH drilling

DTH growing in popularity The DTH drilling method is growing even further in popularity, with increases in all application segments, including blasthole, water well, foundation, oil & gas, cooling systems and drilling for heat exchange pumps. DTH competes favourably with rotary drilling in open pit mines, mainly thanks to increased productivity and flexibility. Open pit mining has adopted smaller holes where rotary drilling has either been replaced by DTH, or where DTH has been introduced to create a better finish to the pit wall, as the method is also perfect for pre-splitting and smooth blasting, which avoids back-cracking. DTH drilling offers increased productivity, and is favoured by contractors for production drilling. In larger quarries, the optimum hole size is 110-165 mm. With today’s demands for strict hole control for safe blasting in populated areas, DTH drilling is a popular choice among quarry operators.

Cutaway section of Secoroc COP 64 Gold.

in joints; and efficient energy transmission, with the piston striking directly on the bit. The COP 34-64 series of hammers was introduced from 1992, and immediately became the benchmark for productivity within DTH drilling. Over the years, the increase in average drilling pressure, from 17 bar to a current market standard of 30 bar, has improved hammer performance, and productivity has increased proportionally to air pressure. The introduction of the Atlas Copco ADS and SDE series of high-performance, high-pressure DTH rigs gave another boost to the sales of

hammers. The flexibility, productivity and maneuverability of these rigs, when equipped with a COP hammer, make them the most productive combination on the market today.

COP Gold series The increase in drilling pressure also had some negative impact on the internal components of the DTH hammer, as the increased stress promoted the risk of premature failures. So, in 1998, Atlas Copco Secoroc decided on a long-term strategy to improve reliability, while

Quality holes In the hole range 100-254 mm, DTH drilling is the dominant drilling method today. The main features of DTH drilling in this hole range are: excellent hole straightness within 1.5% deviation without guiding equipment; good hole cleaning, with plenty of air for hole cleaning from the hammer; good hole quality, with smooth and even hole walls for easy charging of explosives; deep hole drilling capacity, with constant penetration and no energy losses Blasthole Drilling in Open Pit Mining

New Secoroc hammer and bit ready for action on an Atlas Copco drill rig.

37

Talking Technically

COP 64.2 steel COP 64 Gold steel Improvement

Yield point ReL(Mpa) Breaking strength Rm(Mpa) Hardness (HRc)

700 1000 32

1400 1950 42

100% 95% 31%

Table 1 reveals not only that the yield point for the new steel grade is twice as high, but also that breaking strength has been almost doubled.

Table 1 Comparison of COP 64.2 and COP 64 Gold steel.

retaining the benchmark status of the COP DTH hammers. Stage One of this strategy was the development of the second generation six-inch hammer, COP 64.2, introduced in October, 2000, which incorporated newly-designed steel disc spring and lower buffer. Performance was vastly improved, thanks to a drastic reduction in the number of internal failures. It was also possible to rebuild the hammer without diminishing its performance, making it even more attractive. Stage Two was the introduction of the third generation COP 64 hammer, COP 64 Gold, which was unveiled in August, 2001. This version offers sustained performance and improved longevity of the external parts. The COP 64.2 resolved internal component reliability, while the COP 64 Gold has experienced a dramatic drop in the number of cylinder failures. COP 64 Gold also boasts improved sustainable efficiency, maintaining an average of 96% of original performance throughout its service life, which is a further improvement on COP 64.2.

Durability improvements, thanks to the higher tensile strength of the new steel grade, are especially noticeable when the cylinder approaches minimum thickness limits. COP 64 Gold enjoys a greater durability margin than its predecessor. The high demand for COP 64 Gold hammers, particularly in applications where performance and reliability are major considerations, has led Atlas Copco Secoroc to add the COP 54 Gold and COP 44 Gold to this increasingly successful range. In July 2004 COP 54 Gold was released with the same features as the COP 64 Gold and improved performance thanks to a heavier and modified piston and a 12 spline bit shank. Now the COP 44 Gold will be released in Q3 2009. As the other hammers in the Gold Series It will have improved longevity of the external parts thanks to the “Gold” cylinder. Internally it is improved with a heavier piston that will increase the performance and with modified buffers and a steel disc spring the lifetime of internal

parts is extended. And finally a new 12 spline bit shank with 19% more area than DHD340A minimize shank failures in soft or unconsolidated rock.

Hammer cylinder The new cylinder has been redesigned in a number of important ways. COP Gold boasts a cylinder made of lowalloy wrought and toughened steel, a new grade with a higher combined Molybdenum and Vanadium content (4.8%) than its predecessor. The result is greater impact strength and higher wear and temperature resistance. All in all, this means greater resistance to breakage, impact, temperature and wear for the new hammer cylinder. Thanks to the new steel grade, cylinder properties have been greatly improved. Wear has been reduced, both internally and externally. Cuttings and moving parts no longer cause the problems they once did. In effect, the service life of the cylinder has been extended considerably.

Rebuilding With the introduction of COP Gold Series, hammer life will increase substantially. Less internal and external wear, together with a reduced minimum cylinder wear limit, are key contributing factors. As a rule of thumb: If the hammer has reach it’s external wear limits before 5000 drill meters use an

Secoroc COP 54 Gold Express.

38


Talking Technically

Total improvement Due to wear resistance Due to wear limit change Due to less cylinder failure

Increase in service life of COP 64 Gold, which has a 50% longer life than its predecesssor.

Economy Kit and rebuild the hammer, between 5000 and 10 000 drill meters consider to rebuild the hammer and with more than 10 000 drill meters the internal parts could be subject to fatigue failures. Ultimately, this means customers can look forward to increased drill rig availability. The sum total of these improvements shows COP Gold Series to have more than 50% greater service life, in abrasive rock conditions, than its predecessors. The customer benefits from lower cost/metre drilled, thanks to less downtime and greater abrasion resistance, and 30-50% longer life of external parts. Higher availability results from less

breakage in the threads of top sub and chuck-ends of the cylinder, and there are fewer stoppages for service and maintenance. Improved penetration rate and higher efficiency are a result of reduced friction of the piston, and a greater life cycle penetration rate is the overall reward. To sum up, the customer can drill more holes per hammer than previously.

Applications COP Gold Series is high-pressure hammers, where performance is related to air pressure. A lower limit of 12 bar for deep hole applications is a good rule of thumb. The hammer is designed for

the same types of application as COP STD Series, with special focus on highpressure applications. In abrasive formations, performance will be up to 15-50% better than COP STD, in what is an ideal application for COP Gold hammers. In soft unconsolidated rock drilling, the 12-spline chuck concept and the improved durability make COP Gold the perfect hammer. High pressure yields higher productivity, and drilling pressures of 28-30 bar are not unusual. The COP Gold hammer concept offers customers a tool to meet the most exacting requirements.

Leif Larsson

16 000 14 000

Drill metres

12 000 10 000 New Material Old Material

8 000 6 000 4 000 2 000 0 146 145 144 143 142 141 140 139 138 137 136 135 134 133 132 131 130 129 128

Cylinder OD (mm)

Results of comparative tests with COP 64.2 and COP 64 Gold. The COP 64 Gold drilled 50% further.


39

Talking Technically

40


Talking Technically

Selecting the right DTH drilling tools Covering every application Atlas Copco Secoroc now has the most comprehensive range of DTH hammers, bits, and related equipment of any supplier in the world, backed by the strongest support network in the industry. Whether the call is for reliable hammers to keep investment to a minimum, or for the highest productivity to ensure maximum rig output, Atlas Copco Secoroc has the solution. The company is the only manufacturer to offer both first and second choice solutions in almost all typical DTH applications on a price vs performance basis. For premium performance and advanced technology, Total Depth and COP Gold hammers are offered. For an optimum blend of features and cost, COP and Quantum Leap can be the solution, and for high reliability at economical price, nothing beats Fusion hammers. Total Depth, COP Gold, Quan- tum Leap, and COP and Fusion hammers are also energy efficient, consuming less fuel and with lower energy cost per drilled metre than other DTH hammers. This enormous choice of DTH drilling tools is backed by a reliable network of distributors and customer centres that offer a complete range of parts, service and support.

Quarrying application.

Relevant applications Quarrying Companies producing in non-abrasive rock formations should consider hammers such as Secoroc Quantum Leap or Secoroc COP. Both are time-tested and field-proven designs offering good productivity and ease of service. Producers demanding the highest productivity and/or drilling in abrasive formations should consider either the Total Depth or Secoroc COP Gold hammers. These incorporate the latest technology Blasthole Drilling in Open Pit Mining

Changing a Secoroc bit.

41

Talking Technically

incorporating the Quantum Leap cycle, performs particularly well. Geotechnical Environmental monitoring applications will appreciate the Secoroc Fusion, or possibly the Secoroc Quantum Leap or COP hammers. Drilling of holes for foundation, anchoring or drainage demands reliable, inexpensive hammers like the Secoroc Fusion range. Open pit mining Mining operations typically have high equipment utilization, drilling up to 80% of the working day with DTH. The typical applications are normal 130-203 mm-diameter blast holes, 140165 mm buffer holes, or 115-140 mm pre-split holes. Companies should consider either the Total Depth or Secoroc COP Gold hammers. These incorporate the latest technology, and are the most reliable and productive hammers on the market. For customers who are happy with rebuilds, Total Depth is recommended, while for those who typically run hammers until they wear out, Secoroc COP Gold will be the first choice.

Selecting the right hammer

ROC L8.

and are the most reliable and productive hammers on the market. For customers who are happy with rebuilds, Total Depth is recommended, while for those who typically run hammers until they wear out, Secoroc COP Gold has unbeatable wear resistance and will be the first choice. Dimensional stone quarrying demands consistent hole straightness, and such operations typically use smaller size holes of 85-90 mm in limestone, 42

granite and marble. Here the TD 35 and COP 32 hammers are the best choice. Mineral exploration Mineral exploration generally occurs in very remote locations, requiring robust hammers capable of running high pressures, in sometimes dirty environments. For true reverse circulation drilling with face collection in mineral exploration and in-pit grade control, the Secoroc RC50 Reverse Circulation Hammer,

The optimum range of hole size for DTH drilling is 90 mm to 254 mm. Smaller holes are generally drilled using tophammer, and larger holes generally use rotary machines. However, DTH has an expanding position in the larger hole sizes up to 750 mm. As a rule of thumb, the smallest hole diameter a DTH hammer can drill is its nominal size. A 4 inch hammer will drill a 4 inch (102 mm) hole. The limiting factor is the outside diameter of the hammer, because, as hole diameter reduces, airflow is restricted. Maximum hole size for production drilling is the nominal hammer size plus 1 inch, so for a 4 inch hammer the maximum hole size is 5 inch (127-130 mm). Choosing the right hammer is largely determined by hole size and type of rock formation. Ideally, the size of the hammer should match the required hole dimension as closely as possible, leaving just enough space for cuttings to evacuate the hole. Secoroc hammers are purpose-matched for all rock types and applications. Where high performance Blasthole Drilling in Open Pit Mining

Talking Technically

DM45 Blasthole Drill.

is the main criterion, Secoroc COP Gold and Secoroc Total Depth hammers are recommended. In deep hole drilling applications, the Total Depth hammer has proven superior performance and adaptability to different air requirements, thanks to the Air-Select System. Where proven technology is required, the Secoroc COP and Quantum Leap hammers are known for their reliability and longevity, and for a reliable workSoft rock

horse, the Secoroc Fusion is practically bullet proof, with a 30 year history of continuous improvement. The Standard design for COP 54 and COP 64 Gold hammers can be used down to a depth of 330 ft (100 m) using a Standard bit size, making it useful for production drilling in quarries, shallow waterwell drilling, and underground blasthole drilling. HD is similar to Standard, but with heavy duty chuck and wear sleeve, and a top sub

fitted with tungsten carbide buttons for wear protection in harsh and abrasive conditions. These also protect the top sub from excessive wear when rotating out of the hole through broken rock. Highest performance The Secoroc COP Gold and Total Depth hammers are designed for the most demanding drilling conditions and for those applications requiring premium performance. These hammers feature

Medium hard rock (220 Mpa/32000 psi)

Hard rock

Flat front HD SpeedBit Convex/Ballistic Concave Concave DGR Rocket bit ballistic Rocket bit spherical Bit designs and rock types.


43

Talking Technically

Bit designs

Facts Convex/Ballistic front design Convex front with large cutting grooves and ballistic gauge and centre buttons. For soft to medium hard non-abrasive formations. The bit is designed for maximum penetration rate. Also, an alternative in hard abrasive formations, if high penetration rate is called for. SpeedBit Flat front design/ballistic centre buttons. Flat front with spherical gauge buttons and ballistic centre buttons. For high penetration in medium hard to hard abrasive formations.

Flat front design – HD Flat front with large spherical gauge buttons for hard and abrasive formations. Also, front flushing grooves for efficient cuttings removal.

Concave front design Concave front with spherical buttons Perfect choice for medium hard to hard, less abrasive, fractured formations. Minimizes effect of hole d eviation.

Concave front design – HD Concave front with spherical buttons, with larger gauge buttons. Ideal for medium hard to hard, abrasive and fractured formations.

Concave DGR front design Concave front with double rows of spherical gauge buttons. Only available for 8 in bits and larger. The reinforced gauge gives superior protection in medium hard to hard, abrasive and fractured formations. Rocket bit Super high penetration in soft to medium hard formations with low silica content. The Rocket bit also handles difficult formations with clay intrusions where other bit designs will not work.

The Secoroc range of DTH bits ensures that every driller can demand a solution for every application.

44

state-of-the-art technology and deliver both maximum productivity and profit. Secoroc COP Gold • Superior longevity and reliability. • Easy to service and rebuild. • Best suited for production drilling because of its excellent external wear resistance and longevity. • Internal components coated for wear and corrosion protection. Permits multiple rebuilds. • Three start chuck thread for easy bit changes. • Bit replacement possible without using drill rig break-out chains and wrenches. • Unique air cushion reduces wear and tear on drill string and rig. Secoroc TD 70, 80 and 85 • Provides the industry’s highest power output. • Best suited for deep hole applications. • Industry-leading simplicity and serviceability, resulting in very low operating costs. • Features modular components, snap-in cylinders, a reversible casing, backhead saver sleeves, and many options. • The hybrid valved/valveless design maximizes air compressor productivity.

Selecting the right bit Atlas Copco Secoroc has a comprehensive range of DTH drill bits to match all conceivable applications. Each bit is made from quality alloy steel, and has been precision machined to produce a perfect body, heat treated to the required hardness, given surface compression for fatigue resistance, and fitted with precision buttons manufactured inhouse. Five basic designs are available: CV Bit, FF Bit, SpeedBit, CC Bit, and Rocket Bit. These are designed for specific applications for all rock types, hardnesses and conditions. Bit life and rate of penetration are the most important criteria in selecting the right bit for a particular application. In most cases, the focus is on productivity,so the fast cuttings removal Blasthole Drilling in Open Pit Mining

Talking Technically

features of the SpeedBit and Convex/ Ballistic designs are preferable, to ensure the buttons are cutting clean, with the minimum of re-crushing. In hard and abrasive formations, however, the flat front (FF) HD design offers best bit life, having strong gauge rows with large spherical buttons which are easy to regrind and maintain. The SpeedBit offers improved productivity with the same gauge as the FF HD, but with ballistic buttons in the front for faster penetration. An alternative is the Concave design with spherical buttons. The Rocket Bit can be dressed with ballistic buttons for use in soft to medium hard formations where fractured rock can be expected, or can be supplied with spherical buttons for hard and abrasive formations. Bits are manufactured to match all diameters of all Atlas Copco Secoroc hammers.

Selecting the right tube Key features of a high quality DTH tube are durability, accuracy and manageability. Atlas Copco Secoroc tubes are made from cold drawn tubing, providing a superior surface finish and tolerance compared to conventional tubes made from hot rolled tubing. This drastically reduces the risk of scaling from the tubes entering the hammer, a major cause of premature hammer failure. The joints are friction welded to achieve maximum strength, and the threads of the end-pieces are heat treated for optimum durability and strength of the thread profile. This not only ensures long thread life, but also makes coupling and uncoupling quick and simple, reducing drilling time. Tube diameter should be close to the hammer diameter to provide optimum flushing, re-ducing the chances of getting stuck. In most applications, Atlas Copco Secoroc standard API threads will be the best choice. Atlas Copco Secoroc also offers a wide range of subs and crossover subs to meet an array of demands, all manufactured to the same standards as the tubes. Blasthole Drilling in Open Pit Mining

Secoroc COP 54 Gold Express - the production driller´s best friend.

Quality API grade N-80

Standard tubes

End pieces and adapters

min 550

min 550

Tensile strength

N/mm2 N/mm2

min 650

min 700

Elongation A5

min %

18

21

Core hardness

HB

190–230

210–250

Surface hardness

HRC

58–62

Lower yield limit

Drill tube OD (mm)

Wall 23/8" 23/8" 27/8" 27/8" 31/2" (mm) RD 50 API Reg API IF API Reg API IF API Reg

70

3.6

■

■

76

3.6

■

76

5.6

■

89

3.7

■

89

5.7

■

■

■

102

5.7

■

114

4.3

■

■

114

5.7

■

114

7.9

■

45

Talking Technically

With on-site support, the choice of DTH equipment is even easier to make.

COP Backhammer The COP Backhammer is a tool that can save and recover a drill string stuck in a hole. It can be easily fitted in a suitable tube joint between the drill support and the rotation head to provide an effective combination of backward hammering and vibration to loosen stuck drill strings.

Service and support Atlas Copco Secoroc service, support and training follows every purchase, 46

to ensure that customers extract maximum productivity from their drilling operations. Having a knowledgeable and available Secoroc drilling engineer on site or on-line makes the difference between going it alone and tapping the experience and know-how of a worldclass partner. For example, Secoroc knows that using higher productivity bits reduces the cost of each drilled hole, and the simplest way to cut costs is to drill holes faster. This has been a focus of product development, and is at the core of Secoroc technology, ensuring that every generation of products

drills faster and more efficiently. It takes a support team to apply this knowledge, so that customers can be assured they run a profitable and efficient drilling operation in an increasingly competitive business climate. The bottom line is that the customer can count on Secoroc service and support, supplied by the largest, most dedicated manufacturer of DTH drilling tools in the world.

Leif Larsson


Talking Technically

Taking advantage of single-pass drilling The easy way to get more blast holes per day

40' Single-pass, (12.2 m) 50 MPa Rock*

90 2

40 ft

1

80 Overall production rate in metres/hr

Large rotary drills have been in use for years around the world in mining applications. In many open pit operations, these large drills were equipped with electric power and long towers for drilling benches in a single pass. Today, these features are being added to smaller equipment. Let’s look at the benefits of single-pass.

100

30 ft 30' Multi-pass, (9.1 m) 50 MPa Rock*

70 60 50

2 1

40

40' Single-pass, (12.2 m) 100 MPa Rock*

40 ft

30 ft

30 30' Multi-pass, (9.1 m) 100 MPa Rock*

20

Longer towers The drilling of large diameter holes, generally considered to be greater than 9 inches in diameter, is done predominantly with rotary blasthole drills. One of the reasons for this is that larger diameter tricone bits allow for large bearings to handle high pulldown forces to drill through hard rock quickly. These high pulldown loads require a heavy tower structure to transmit these pulldown forces to the drill bit. Further, this high pulldown must be offset by sufficient mass to keep the drill rig from lifting off the ground. The resulting rig is therefore quite heavy. With a heavy, durable rig already dictated by a large hole diameter, drill designers are able to take advantage of the large platform to offer longer towers capable of drilling benches in one pass. This often drives a change in structural design and supporting components such as undercarriages, but the basic rig envelope doesn’t change. Drilling a hole in one pass has many advantages.

Elimination of rod changing time Adding a rod may take 45 to 60 seconds depending on the size of the rig, and taking the rod back off may take Blasthole Drilling in Open Pit Mining

10

* Compressive strength

0 0

2

4

6

8

10

12

14

Drill depth in metres

Fig 1. Comparison of single-pass and multi-pass drilling,  = Time lost for rod adding and rod removal,  = Lost productivity for multi-pass drilling.

60 to 90 seconds. The extra time for removing a rod is due to the extra cycle required to lower the head to pick up the next rod. The effect of rod changing time is more dramatic in soft material, as shown in Fig 1. Surprisingly, it is the large metals mines that pioneered the use of single-pass drills, even though they may see limited productivity benefit. In extremely hard rock such as that encountered in taconite, the single-pass benefit might only be 3 percent. At the other extreme would be very soft coal overburden. This material can be drilled with claw-type bits at rates of 400 meters/ hour or more. In this situation, a singlepass drill would yield an overall productivity gain of over 25 percent.

Simplified operation Even in situations where the productivity gain from eliminating rod changes is relatively small, there are benefits. Operators don’t have to worry about the rod changing operation, which consists of 10 actions to add a rod and 13 actions to remove a rod. Eliminating these tasks during each hole reduces the chance for errors such as crossthreading the tool joints on the drill rods or dropping a rod. Tasks such as changing a bit in the middle of the hole or reaming the hole to clear out cuttings are much simpler when you don’t have to add or remove rods. These factors could increase overall productivity by a few more percent.

Fig 2. Single-pass Pit Viper rigs Rig

PV-235

PV-271

Hole range

152-251 mm (6-9 ⁄8")

171-270 mm (6¾-10 ⁄8") 270-406 mm (10 5 ⁄8 -16")

Single pass depth

12.2 m (40 ft)

16.8 m (55 ft)

7

PV-351 5

19.8 m (65 ft)

47

Talking Technically

Committed to superior productivity: Single-pass Pit Viper drill rigs such as these at Phoenix Mine, Nevada, will continue to be developed for smaller dimension drilling.

Less maintenance

Safety factors

The carousel and wrench systems used routinely in multiple-pass operation are high wear items due to the nature of their operation. While they may still be used on single-pass drills, especially for changing drill bits, they see a much lower duty cycle. As mentioned above, tight drill tool joints can be a problem. Improvements in breakout wrench systems have helped address these issues, but it is still common to see joints that can’t be broken by onboard wrench systems. Given the advantages above, why wouldn’t every drill be built as a singlepass? Obviously, it isn’t practical to build a unit to support a 70 meter hole in coal overburden. It may be possible, but you’d end up with a unit with a mast as long as a dragline boom. The expense of such a unit would probably never be recovered with the operating cost savings.

As towers grow in length, the supporting mainframe and undercarriage must grow as well. To maintain the structural life and reliability of smaller multiplepass units, proper safety factors must be used in the design. The result is a larger and more expensive machine than customers are willing to buy. An example would be the move from the DM-M2, a multiple-pass unit with 35-foot drill rods and a gross weight of about 57 tons, to the single-pass Pit Viper 271 for 16.7-meter holes. The Pit Viper 271 weighs in at around 80 tons. Many smaller rotary drills operate on slopes that could not be considered firm and flat. While single-pass drills might be capable of operating on a minor slope (less than 10 percent), they will generally have a higher center of gravity than their multiple-pass equivalent, reducing the stability of the unit. This is often the operator’s perception

48

as the unit may be capable of slopes that might be substantially more. However, many factors must be taken into account when determining whether to operate on a particular slope. Ground conditions are rarely a single plane. Instead, they are compound angles of widely varying rock size and type. Most operators err on the side of limiting the slope they will attempt to navigate. Thus, single-pass drills are viewed as being limited to flat benches only. As we say at Atlas Copco, we are committed to our customers’ superior productivity. We will continue to develop single-pass units for smaller diameter operations. While we have several smaller units already capable of singlepass (the DM25SP and DML-SP), they are rotary table drive units. They utilize lightweight towers on relatively small base units by locating the feed and rotation mechanisms towards the bottom of the tower. The drawback of this design is that rotation is accomplished through a rotary table drive that engages a fluted kelly bar, driven mechanically by drive pins. The kelly bars are very expensive due to the fluting milled into them, and if the material is abrasive, they wear quickly and result in high operating costs. However, in soft applications, they are a great option. As most of our applications involve harder, abrasive material, we are looking to develop tophead-drive units with longer towers. Adding to our fleet of large single-pass units, as outlined in Fig 2, we are testing the new Pit Viper 235. It is equipped with 40-foot drill rods and can single-pass drill 12.2-meter holes, which is ideal for many metals operations. In designing this unit, the engineering team strived to address the perceived stability issue that turns some mines away from single-pass. The result is a unit that is more stable than our DML with 35-foot drill rods and a 9.5-meter capability. We encourage our customers to look at single-pass drilling as it is one of the easiest ways to get more holes per day.

Brian Fox


Talking Technically

Blasting in open cut metal mines Explosives Since blasting was introduced in mining as part of the production process, blasting technology and blast management have been inter- connected. Explosives have been the primary method of breaking and loosening rock since the introduction of black powder. Over the years, however, blasting technology such as the physical properties of explosives and types of detonators has evolved. The same holds true for the process of blast management – from design principles for production blasts that are cost-effective and optimize mining operations, to safety and accident prevention during every step of the drilling and blasting process. Drilling and blasting results have a major impact on many processes in a mine. Therefore, it is important to find the right combination of drill pattern, explosives and blast design to contribute to the economic success of the total mining operation.

Principles When properly initiated, commercial explosives are rapidly converted into gases at high temperature and pressure. When detonated unconfined, a liter of explosive expands to around 1000 litres of gas in milliseconds. When confined by rock, expanding explosion gases result in extremely high stresses in the rock. The gas energy released during detonation acts equally in all directions but tends to escape through any path of least resistance. Therefore, blastholes should be charged and stemmed so that the gases are confined for sufficient time to provide optimum breakage, displacement and looseness of the blasted rock. The majority of explosives used in today’s surface metal mines are primersensitive explosives. Under normal conditions of use, a primer is required to initiate them reliably. All primer-sensitive explosives cotain the following essential components: Blasthole Drilling in Open Pit Mining

Blasting at the Aitik Mine in northern Sweden.

• An oxidizer: a chemical which provides oxygen for the reaction. Ammonium nitrate is the most common oxidizer; • A fuel: which reacts with oxygen to produce heat. Common fuels include fuel oil and aluminum powder; • A sensitizer: which provides voids that act as “hot spots” where the reaction starts during detonation. Sensitizers are generally air or gas in the form of very small bubbles, sometimes encapsulated in glass microballoons (GMBs). An explosive is classified as detonatorsensitive if it can be reliably initiated in an unconfined state by a #8 strength detonator (which has a base charge of 0.46 g of PETN). Detonator-sensitive explosives may or may not contain ingredients that are themselves explosives.

Properties of explosives The physical characteristics of the various types of explosives differ markedly. For example, ANFO type explosives are loose, free-flowing, granular compositions, whereas emulsion explosives have a consistency that varies from that of

syrup to firm putty. There are also various blends of emulsion and ANFO type explosives, notably so-called heavy ANFOs. Watergel (slurry) explosives are also used in some countries. The physical properties of the explosive can dictate the handling system used to charge the explosive into blastholes.

Water resistance

The water resistance of explosives varies considerably. Emulsions have excellent water resistance; heavy ANFOs have some water resistance while ANFO has negligible water resistance.

Density

The in-hole density of explosives has a significant effect on the energy per meter of charge length. Higher-density explosives generate more energy. Explosives are supplied in different densities to enable the shotfirer to control the total energy released in a blasthole to suit the particular blasting conditions and to achieve the desired result.

Sensitivity

Sensitivity is a measure of the ease with which an explosive can be initiated by 49

Talking Technically

responsible for conditioning the rock and initiating mechanisms that generate fractures. The “gas energy” or “heave energy” is delivered during the later expansion of the explosive products into the crack network of the rock. Once a fracture network is established the gas is able to expand into the network, both extending the fracture process and causing movement of the rock. As this happens, the gas pressure drops until it vents to the atmosphere.

Drilling at the Aitik Mine, northern Sweden.

heat, friction impact, or shock. The trend in commercial explosives is towards lower sensitivity to initiation without detracting from detonation efficiency.

Critical diameter

The critical diameter of an explosive is the diameter below which a stable detonation does not occur. To ensure reliable initiation under normal conditions of use, explosive suppliers recommend a minimum diameter for each of their products. To ensure reliable results under most conditions, the recommended minimum diameter is larger than the critical diameter.

Desensitization

Most explosives become less sensitive at higher densities. Desensitization can occur at excessive hole depths due to the static head of pressure. It is also possible for explosives to be dynamically desensitized by nearby earlier firing charges.

Velocity of detonation (VOD)

VOD is the speed with which the detonation propagates through a column of explosive. Two explosives having the same strength but different VOD may perform quite differently in a blast. As a general rule, the higher the VOD, the greater the shock energy and the lower the heave energy. However, it is important not to correlate shock energy directly with fragmentation energy. 50

The VOD of explosives used in surface metal mines vary between about 3000 m/s and 7500 m/s. The VOD of many explosives increases with charge diameter and confinement. Because of their high degree of refinement and efficiency, emulsion explosives can maintain very high VOD even with poor confinement and in small diameters.

Energy/strength

The energy of an explosive expresses the ability of the explosive to do work. An explosive with greater energy will be able to do more work on the surrounding rock. Energy produced by an explosive can be calculated using thermodynamic codes and measured using a variety of techniques.

Primer-sensitive explosives

Primer-sensitive explosives have relatively low sensitivity to shock, friction and impact, resulting in excellent safety and handling characteristics. The reliable detonation of primer-sensitive explosives requires initiation by a primer (e.g. Pentex™) that is in good contact with the charge. Ammonium nitrate is the major ingredient of most primer sensitive explosives.

Shock energy, gas energy and heave energy

Following detonation, high-pressure gases compress and crush the rock immediately surrounding the explosives. This results in an increase in the size of the blasthole and will vary according to the characteristics of the rock. The energy that is released by the explosive can be partitioned into two main types, the shock energy and the heave energy. The shock energy that is delivered to the rock is related to the extent and the rate of the borehole expansion to a socalled equilibrium state and includes the effects due to sub-optimal initiation. The energy delivered thus far is termed “shock energy,” which is primarily

Detonator-sensitive explosives

Detonator-sensitive explosives include Pentex™ boosters and Senatel™ packaged emulsions, which can be reliably initiated by a single #8 strength detonator or by a strand of 10 g/m detonating cord.

Initiating systems

Initiating systems are used to safely initiate charges of explosives at predetermined times by carrying a firing signal from one place to another, using chemical or electrical energy. Blasthole Drilling in Open Pit Mining

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Modern initiating explosives incorporate various explosive and inert components, which are partly or wholly consumed in the blast. Small quantities of signal tubing or wire often remain in the muckpile. Non-electric initiating explosives use pyrotechnic compositions or explosives to store and transmit energy by controlled shock waves, detonation or burning. Electric initiating systems require an exploder to generate an electrical charge, which is transmitted along wires. Blast timing is usually controlled by pyrotechnic (burning) delay elements located inside detonators. Non-electric initiating systems based on a signal tube are currently the most widely used for blasting in surface metal mines. Most mines now use nonelectric detonators inside blastholes, with remote initiation of blasts using a non-electric firing system. Electronic blasting systems are becoming more common, and differ from electric and non-electric delay systems in that the delay time is controlled by a programmable integrated circuit, resulting in very precise timing. The accuracy and programmability of electronic detonators allows for blast timing to be tailored to the geometry, geology and unique requirements of any blasting operation to more effectively use explosives energy.

Examples of initiating systems produced by Orica (MMU ®) services.

Bulk explosives

Specialized equipment and tools are required to safely and effectively mix and charge explosives in surface metal mines. Most of the equipment and tools used in blasting operations are subject to statutory regulations. A Mobile Manufacturing Unit (MMU®) is effectively an explosives factory on wheels. Each MMU® is designed to produce and deliver specified bulk explosives from a manufacturing unit based on a conventional truck chassis. Orica MMU®s are able to carry large quantities of non-explosive raw materials to the mine site, avoiding the need to carry explosives on public or mine roads. The bulk explosives are manufactured at the blasthole collar and accurately delivered into blastholes at high discharge rates. MMU®s are producedin a variety of configurations to Blasthole Drilling in Open Pit Mining

Orica Mining Services offers a total loading service to its customers.

51

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indicate alternative superior designs. Initial blast designs must then be progressively improved to optimize mining operations and costs. Optimum designs help to produce the required fragmentation, muckpile looseness, muckpile profile, toe conditions and grade control. In some cases, blast designs must also minimize flyrock and control ground vibrations and air overpressures.

Design variables

The Mobile Manufacturing Unit on site (MMU ®).

meet specific needs. The complexity of the onboard manufacturing facility depends on the type and number of explosives required. The truck on which this is mounted is selected to suit the material to be carried and the terrain on which it will operate.

Explosives selection, priming and charging Priming and charging of blastholes is one of the most important parts of a successful blast. Blastholes must be accurately primed and charged to the design specified by the blast designer. The objective when selecting a combination of explosives is reliable performance, which will ensure the lowest overall operating costs without sacrificing safety. When selecting explosives, the principal considerations are: • Ground water conditions; • The properties of the rock being blasted, i.e. strength, structure, etc.; • The diameter and depth of blastholes; • Drilling costs and drilling capacity; • The relative explosives cost per unit of effective energy; • The fragmentation and heave characteristics of the explosives; • Shelf life; • Desired results. ANFO has proven to be the most cost-effective method of blasting dry blastholes. ANFO has relatively low 52

fragmentation energy, high heave energy, and is extremely effective in all but the toughest, most massive rock types. Wet blastholes ideally should be charged with a water-resistant explosive, either an emulsion or a watergel. The explosive will displace the water up the hole, which may flow into adjacent dry blastholes. Other options that may be considered are: • Dewater the holes using in-hole pumps, compressed air or other means, and then treat them as blastholes containing nuisance water by charging with water-resistant bulk or packaged explosives to above the original water level, then continuing with ANFO. • Charge the wet blastholes with packaged explosives until above the water level. Then charge with ANFO.

Blast design When starting to work a new mine or a new area of an existing mine, it is necessary to develop one or more initial designs for production blasts. In this situation, some “rules of thumb,” derived over many years of relevant practical experience, should be used for developing these designs. If a detailed assessment of rock mass properties has been carried out, computer modeling can be used to assess the suitability of the designs developed, and possibly to

Bench height normally lies in the range of 5-18 meters The selected bench height is influenced by: • Statutory regulations (excessively high benches are unsafe and, therefore, not permitted); • Rock mass properties; • The type and size of digging equipment; • Grade - control requirements; • The need to maximize the overall cost efficiency of drilling and blasting. Increasing bench height decreases total drilling consumption of primers and initiators, the labor required for firing, and the number of mining cycles. Optimum blasthole diameter increases with bench height. In general, an increase in blasthole diameter decreases the total cost of drilling. Drilling accuracy becomes more critical in higher benches and drill deviation can produce costly consequences.

Blasthole diameter

Optimum blasthole diameter is greater for higher benches and for larger digging, hauling and crushing equipment. Large diameter blastholes are less suitable in strong, massive rock; when minimal broken rock movement is required; or where it is very important to control blast vibrations. At large surface mines, the total cost of mining is usually minimized by drilling large diameter blastholes. Larger diameter blastholes reduce costs for drilling, primers and initiators and labor. They usually need higher powder factors than small diameter blastholes to give the same fragmentation, especially in strong rocks. Smaller blastholes give better distribution of energy in the rock mass. Blasthole Drilling in Open Pit Mining

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Free faces

Effective free face

Forward displacement of blasted rock occurs if a blast shoots to a free face (Figure 1). Some movement of the rock mass is necessary to allow for crack propagation. Increased movement assists crack propagation and can improve fragmentation. This may not be the main objective in some operations (e.g. blasting in ore) so free faces may be limited (choked) to restrict ore dilution.

Blasthole angle

Vertical blastholes are usually used in surface metal mines because: • Angled blastholes are more difficult to set up and drill; • Some drills do not have an angled drilling capability; and • Drilling accuracy is greater with vertical blastholes. In free-face blasting, vertical frontrow blastholes often leave variable and excessive burdens between the top and bottom of the charge (Figure 2). This variation is greater in high- or shallowdipping faces and can cause hard, immovable toe. Front row blastholes collared near the crest to control the toe burden can cause explosion gases to blow out prematurely in the face. (See Figure 3 and 4) This blow out creates noise, airblast and flyrock and reduces blasthole pressure near the bench floor level, which may prevent adequate breakage and movement of the toe. This may necessitate the use of some angled blastholes in front rows. (Figure 5)

Subdrilling and drilled length of blasthole

Efficient excavation needs toe conditions that suit the digging equipment. Toe conditions are affected strongly by the amount of effective subdrilling. Subgrade or subdrilling is the length of the explosive charge, which lies beneath the designed bench floor level. Unavoidable fallback of drill cuttings and small rock fragments reduces the effective subdrilling to less than that originally drilled. It is good practice to drill a certain extra distance (which is longer for higher benches and weaker rocks) to allow for unavoidable fallback. Blasthole Drilling in Open Pit Mining

Fig 1. Effective free face.

Caution! Excessive Burden

Airblast Flyrock

Required Burden Fig 2. Variable burdens, vertical holes.

Fig 3. Excessive blasthole angles cause problems.

Airblast Flyrock

Caution! Correct Burden

Fig 4. Problems with variable burdens.

Fig 5. Angled holes increases rock breakage.

Priming

Bottom priming has several advantages over top priming. They include: • Improved fragmentation, displacement and muckpile looseness; • Reduced toe problems, better floors, and cleaner faces; • Reduced noise, airblast, flyrock and surface overbreak; and • Fewer cut-offs and misfires.

The overriding concern in priming is to locate the primer in the explosives column and ensure operational safety and efficiency. The primer is generally placed at or near grade level. Some operators place the primer at a known distance above or below bench floor level to ensure that, should a misfire occur, the excavator operator does not dig directly into a primer. This may be a valid reason for not placing the primer at bench floor level.

Charge distribution

Distribution of the explosive charges in the rock mass is an important 53

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consideration when determining blast geometry. Crater blasting to a horizontal rock surface has a less efficient charge distribution but is preferred in shallow ore deposits where quality control dictates low benches, despite a higher explosives consumption.

Blasthole pattern

(a) (a) Paddock Paddock blast blast –– staggered staggered

(b) (b) Paddock Paddock blast blast –– square square

Blasthole patterns depend on blasthole diameter, rock properties, explosive properties, bench height, and the results needed. Operating experience and blast modeling results have shown that, in massive rocks, better fragmentation and productivity are obtained with staggered patterns than with either square or rectangular patterns. Equilateral triangular patterns provide optimum distribution of explosion energy in the rock. While staggered patterns give the best theoretical performance, the initiation sequence can alter the geometry and results of blasts on square or rectangular patterns.

Spacing-to-burden ratio

(c) (c) Paddock Paddock blast blast –– rectangular rectangular

Burden and spacing are related to blasthole diameter, depth, rock type and charge length. Blasthole spacings considerably smaller than the burden tend to cause premature splitting between blastholes and early loosening of the stemming. This can cause premature release of explosion gases to the atmosphere and considerable overbreak. Loss of heave energy reduces breakage and produces large rock slabs in the muckpile. On the other hand, a spacing-to-burden ratio that is too large can cause the face midway between back-row blastholes to remain intact, especially near bench floor level. This results in tight digging and possibly unbroken toe.

Front-row blastholes

d) Square – Fired on Echelon Fig 6. Blasthole patterns.

54

Special attention should be paid to the position of front-row blastholes. If the burden on front-row charges is excessive, it will not be broken by the time second-row charges detonate. Restriction of motion at the beginning of the blast can prevent optimum blasting results throughout the blast. Where burden is too small, explosion gases burst rapidly through the face, causing noise, airblast and flyrock. Blasthole Drilling in Open Pit Mining

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Changing burden and spacing

Changes in burden generally affect fragmentation, muckpile looseness and toe much more rapidly than changes in spacing. If enlarging a blast pattern for improved economy, it is more common to increase the blasthole spacing in steps before altering the burden.

Stemming

Stemming enhances fragmentation and rock displacement by reducing premature venting of high-pressure explosion gases to the atmosphere. (Figure 7) Dry granular materials are best for stemming because they have inertial resistance and high frictional resistance to ejection. Materials that behave plastically or that tend to flow are not suitable for stemming, e.g. water, mud, wet clay. Stemming length can be reduced significantly if effective stemming is used, resulting in better explosive distribution and improved overall fragmentation. Optimum stemming length depends mainly on blasthole diameter, stemming material, and surrounding rock properties. Inadequate stemming increases collar rock breakage, but decreases overall fragmentation and displacement because explosion gases vent to the atmosphere more easily and rapidly. It also creates more flyrock, surface overbreak, noise and airblast. Long stemming lengths ensure good confinement of explosion gases, but fragmentation of collar rock becomes coarser.

Size and shape of blasts

Most oversize rocks come from the back, sides and top of blasts. Boulders are created by open fractures in the free face, irregular burdens and by backbreak around the perimeter. Damage from previous blasting around the perimeter opens fractures which define rocks isolated from the rock mass. These rocks are not fragmented by explosion-generated strains and cracks, but are merely pushed forward into the muckpile. In addition, large rocks that have been torn loose or dislodged can slide from the new faces into the muckpile. Increasing the blast size reduces the proportion of large rocks from the blast perimeter, and therefore improves overall fragmentation. Blasthole Drilling in Open Pit Mining

(a) Excessive Airblast & Flyrock

(b) Good breakage & displacement (c) Poor fragmentation

Fig 7. Effect of correct and incorrect stemming.

Allocation of delays

The sequence in which blastholes are initiated and the time interval between successive detonations has a major influence on overall blast performance. The performance of production blasts can only be optimized when charges detonate in a controlled sequence at suitable discrete, but closely spaced, time intervals. Optimum delay allocation for a blast depends on many factors, which include: • Rock mass properties (strength, Young’s modulus, density, porosity, structure, etc.); • Blast geometry (burden, spacing, bench height, free faces, etc.); • Diameter, inclination and length of blasthole; • Explosive characteristics, degree of coupling, decking, etc.; • Initiating system (surface or in-hole delays, type of downline, non-electric or electronic, etc); • Type and location of primer; • Environmental constraints (air and ground vibration levels and frequency); and • The desired result (fragmentation, muckpile displacement and profile etc.). It is not possible to determine optimum delay allocations from first principles, but blast monitoring, analysis and interpretation have led to a greater understanding of the mechanisms and significance of blasthole interaction.

Delay along rows

The delay time between adjacent blastholes in a row is sometimes called the intra-row delay. Firing a single row of blastholes with the optimum delay between holes produces: • Optimized fragmentation for that particular blast geometry; • Forward displacement, which is less than that for an instantaneous singlerow blast; and • Reduced overbreak.

Delay between rows

The delay time between the initiations of rows of blastholes is sometimes termed the inter-row delay. The delay between rows can be as important as the delay along rows in controlling overall blast performance. Multi-row blasts are fired using a time delay between the detonations of successive rows of blastholes. The burden on each blasthole needs time to move after the detonation to create an effective free face. Dependent blastholes then fire towards this new free face developed during the blast. (Figure 8)

Hole-by-hole initiation

In many situations the simplest method of blast initiation hook-up is to fire blastholes row by row or simultaneously along echelons. This will rarely produce optimum blast performance, especially in terms of fragmentation or ground vibrations. The end result can be improved by introducing hole-by-hole 55

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3

2

between the back row and the pit limit is too small, there will be too much overbreak into the final face. If the standoff distance is too large, digging back to the design final face will be difficult, expensive and may need a bulldozer. (Figure 9) • Blasthole depth– If blastholes are drilled into the berm below then the succeeding wall will be damaged. Sufficient standoff distances need to be maintained to designed crests.

1

(a) Good "Relief"

Smoothwall blasting techniques

2

1

3

(b) Insufficient "Relief" Fig 8. Burden relief.

firing, where every blasthole is initiated in sequence at a unique time. Where appropriate delays are selected, hole-by-hole initiation exploits the positive benefits of blasthole interaction while avoiding most of the negative effects. This leads to improved fragmentation and muckpile looseness, reduced overbreak, lower ground vibrations, and better control over the final muckpile position and profile.

Final wall blasting

At most open pit mines, the final slope of the pit affects profitability appreciably. Steep stable pit walls can be formed by smoothwall blasting techniques, which include cushion blasting, presplitting and postsplitting. But with each of these techniques, the combined cost of drilling and blasting is relatively high. In some cases, stable pit walls can be formed without smoothwall blasting. 56

Careful blast design is the key to producing clean, safe pit walls at minimum cost. The blast design needs to consider the rock conditions in the area, the likely amount of backbreak from this blast, and the design location of the final pit limit. Key factors to consider in final wall blasting are: • Geology – Rock properties have the greatest influence on the effect of blasting on pit walls. Heavily jointed rock often produces overbreak along joint planes. • Blasthole location – The location of the back row of blastholes is critical to the location of the final pit limit. The back row of blastholes needs to be drilled in front of the final pit limit to allow for backbreak behind the blastholes. The correct location depends mainly on previous experience in the pit and trial and error, particularly if the amount of backbreak is variable. If the standoff distance

Cushion blasting, postsplitting and presplitting are the three common blasting techniques used to produce stable final walls. Postsplit and presplit blasts are often used alone to produce stable walls. Cushion blasting is frequently overlooked when designing final-wall blasts, but can be the most versatile and useful method of the three techniques. The back-row blastholes in a cushion blast contain lighter charges than the production blastholes, and are drilled on a correspondingly smaller pattern. Cushion blastholes are usually the same diameter as the production blastholes in front of them. Charge weight is commonly reduced by about 45 percent, and both burden and spacing by about 25 percent. The energy factor is therefore essentially the same throughout the final wall blast. A postsplit blast consists of a row of parallel, closely spaced blastholes drilled along the final face. These blastholes are charged with a light, welldistributed charge, and fired after the production blastholes in front have detonated. Postsplit blastholes split the rock web between the blastholes to produce a sound smooth face with minimal overbreak. Presplitting requires a row of closely spaced blastholes drilled along the design excavation limit, charged very lightly, and detonated simultaneously before the blastholes in front of them.

Special blasting techniques While the main emphasis in surface metal mines is on production blasting, Blasthole Drilling in Open Pit Mining

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there are times when special blasting techniques are required. These include: • Opening up new benches using either drop cut or ramp blasting • Mining of weathered and fresh rock • Dilution control • Choke blasting • Blasting ore and waste together • Steeply dipping multi vein orebodies • Shallow dipping narrow vein orebodies • Flat or bedded orebodies • Selective ore blasting • Separate ore and waste blasting • Deck charging • Secondary blasting and popping • Plaster blasting • Floor and toe blasting

Could be Presplit

Production Blastholes

Final Limit

Maybe Smaller Diameter

Reduced Energy per m

Safety and accident prevention

Safe and cost-efficient blasting requires all mine operators and supervisors to understand and follow correct procedures for handling and using explosives. Most mines now have on-site induction training to develop skills for specific jobs, including blasting. Many mines have written work procedures, which specify the method, tools and equipment to be used for each job. These procedures, combined with local mine rules and statutory regulations, are designed to maintain the health and safety of all people working in the mining environment. Blasting requires the use of special tools and equipment, which are usually subject to statutory regulations. All tools and equipment used for charging and firing explosives should be properly maintained, regularly checked and correctly used. There should be no improvisation or substitution, as this can cause injuries and accidents. There are many hazards when working in and about a mine. The additional hazards associated when using explosives that need to be mitigated are: • Electrical hazards that can affect the use of electric detonators. The sources of electrical current are static, stray currents from machinery, lightning and radio frequency energy. • Heavy impact on initiating explosives • Vehicles driving over explosives • Hot and reactive ground Blasthole Drilling in Open Pit Mining

No Subgrade Final Limit

Fig 9. Placement of blastholes along final pit limits.

• Misfires • Fume • Walking on rough ground and around blast holes • Vehicle and pedestrian congestion on the bench

Charging blastholes safely

Before charging commences, the blasting area should be barricaded and marked with cautionary signs and lights. All unnecessary tools, equipment and people not involved with blasting should be removed from the area. Smoking must not be permitted near explosives or charging operations. The quantity of explosives delivered to the job should not far exceed immediate requirements, and any unused explosives must be returned to the magazine when charging has been completed. Explosives and detonators must be kept apart in separate containers until charging commences. These containers should be located in a safe place, clear of equipment, and marked by appropriate signs or lighting. Electric detonators must be kept clear of all sources of electricity and all

potential conductors of stray currents. Electric detonators should be kept coiled, with the lead wires shorted together, until they are used. All blastholes should be cleared of obstructions and checked for length before charging. Drilling sludge and loose rocks should be washed or blown out before charging.

Economics and benefits Cost effectiveness of drilling and blasting can be defined in many ways, but the “bottom line” is that these operations must contribute to the best overall economic result for the total mining operation. Drilling and blasting influences many different processes in a mine, with the benefits of a cost-effective blast being felt anywhere from digging to maintenance, hauling, crushing and milling, ore recovery to labor utilization and secondary breakage. Therefore, decisions on drilling and blasting need to be made in the overall context, and should not generally be based on short-term economic factors. The development and introduction of bulk explosives and efficient delivery 57

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Cost per Tonne

Total Costs

Unit Costs ($)

Zone of Minimum Total Costs

Load & Haul Crushing

A Drill & Blast

B

Secondary

C

Fragmentation Fig 10. Costs versus fragmentation.

systems has provided a quantum step forward in blasting efficiency and has allowed cost reduction through economies of scale. The factors contributing to economic production in mines include:

Productivity

• Overburden/waste removal • Primary raw feed/mine production/ sales tonnage • Mobile equipment capacity/type and availability • Fixed plant capacity/type • Ore grade control factors • Maximizing reserves through structural stability • Minimizing stripping ratio: waste/ ore

Mine conditions

• Type and extent of overburden/ waste • Rock type and geology • Height and inclination of operating benches • Ground water conditions • Environmental constraints

Labor force competence • Training • Motivation and numbers

Operating costs vs fragmentation Drilling and blasting results have a major impact on each part of a mine's 58

operations. The optimization criteria for mine production operations can be expressed as finding the right combination of activity costs, and managing them in order to minimize the overall production costs (Note: this does not mean that reducing any particular parameter in isolation will necessarily result in a lowering of overall costs). Figure 10 schematically represents the activity costs as a function of maximum fragmentation size. The relationship between these activity costs varies from mine to mine. The curve is divided into three zones – A, B and C. Zone B is where the total costs are minimized within a controllable and acceptable range. In zones A and C the unit costs of one or more activities make the overall production cost excessive. In this case, the cost effectiveness of blasting does not necessarily increase with a decrease in blasting costs, and changes can often be counterproductive. The best time to break rock is undoubtedly during the primary blast– the aim being to achieve desired and predictable fragmentation, muckpile looseness, and a suitable muckpile profile for ease of digging. During the evaluation, other key issues may be: • To modify fragmentation to suit excavator or crusher specifications; • To make blasting more environmentally acceptable; • To improve labor utilization allocated to blasting;

The PV-351 can drill blastholes up to 16 inches in diameter.

• To reduce blasting costs, particularly in wet areas; • To protect pitwalls or control overbreak damage; and • To maximize recovery of product ore. The process of optimizing blasting must be done in a controlled manner so that the inf luence of changes on blast performance can be measured and evaluated. It is most important that changes are made one at a time, and that a thorough analysis of the total cost and the blast performance are made to enable any benefits to be identified and quantified.

Acknowledgements Article produced by Orica Mining Services, the world's largest provider of commercial explosives and blasting systems. Blasthole Drilling in Open Pit Mining

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Drilling in Arctic conditions Coping with climatic extremes The spread of mining to inhospitable parts of Mother Earth has posed a major challenge for mining equipment design engineers in terms of both basic machine functions and operator well being. Ope- ration at high latitude or high altitude requires a significant degree of redesign. Available coal and mineral resource geography has intensified, first with exploration and then mining activity, in the Arctic and sub-Arctic central continental regions of North America and Asia. In parallel the ability to build equipment that can operate economically at temperatures around -55°C has become increasingly important. Similarly, the development of mines at high altitudes requires machines that can cope with low atmospheric pressure as well as low temperature.

The Russian experience For rotary drill rigs the key base materials adversely affected by low temperature operation are steel, rubber and lubricants. • At lower ambient operating temperatures steel becomes brittle, creating possible earlier fatigue failures. For heavy equipment designers, the task is to select steel with proper material properties, to reduce the load or to reduce the loading cycles. Through the combination of the three factors, structural integrity can be equalled to equipment running in non-arctic conditions. • With any rotating equipment, seals and hoses are used to retain fluids. Like steel, the newer generation synthetics lose f lexibility, becoming brittle. With arctic conditions, the key is again through material selection to keep equipment doing its primary function without the aid of artificial heat sources. In an arctic Blasthole Drilling in Open Pit Mining

Exposure and constant ground contact subject the crawler undercarriage to particular abuse in low temperature, icy conditions, requiring careful selection of materials. Some applications may require heating the drive elements to keep them working.

application the use of natural rubber or silicon is better than synthetics. • To maintain acceptable component life in arctic conditions effective lubrication is essential. Typically this will require using the standard additives with a base lubricant that will flow at the ambient temperatures and at the viscosities specified for the application. Beyond making necessary changes to base materials, subsystem redesign may be required to meet the low temperature challenge. Engineers must decide if the material can be changed, heat be added or in some cases the part be eliminated to achieve 5,000 to 6,000 operational hours per year.

Exposure and constant ground contact subject the crawler undercarriage to particular abuse in low temperature, icy conditions. Many components either rotate or articulate (rollers, idlers, drive sprockets and track chains). Again the driver is to upgrade the base material, steel and rubber, where necessary. Some applications may require heating the drive elements to keep seals soft and pliable. Similarly, for a diesel engine powering the rotary rig in these conditions, special attention must be given to startup and lubrication. Atlas Copco has designed a series of heater packages for lubricants, the engine block and batteries. All these packages are powered by 59

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110, 240 or 380 V AC electricity provided by the mine electrical grid or a diesel generator. If getting electrical power to the drill is impossible, a dieselpowered block heater is another option available. Likewise if low ambient fuel is not available use of 24 V DC fuel heaters is yet another option available. Lubrication systems pumping grease over long distances can be impossible, and it may be best to redesign with a component that has impregnated oil bushings or closed bearings. To prevent the pump from cavitating, the lubricant will either have to be heated or replaced by a special blend that maintains viscosity through the ambient temperature range. Dust suppression is most difficult in low ambient climates. The synthetic rubber normally used in dry dust collectors becomes brittle in extreme cold, and articulated components such as hoses and dust curtains will fail. If the drop out chute does not close properly the system fails to back flush. Also moisture entering the collector will freeze when it enters the cold dust collector chamber. Vibrators can be used to prevent material collecting on the dust collector body. Another option under development is a wet dust control system. To keep the system from freezing is a design challenge. In this case short hose connections with diesel fired pre-heaters create enough energy to keep the system in operation.The benefit with wet systems is the reduced number of moving parts. Given that the time limit for human exposure to very cold air is 15 minutes, the cab for artic rigs must be big enough for two operators and their cold weather clothing. Additional insulation, heating and defrosting capability are also essential. The marriage of low temperature solutions and advanced technology on Atlas Copco Drilling Solutions rotary blasthole drills has been successful. Today over 150 Drillmaster and Pit Viper class rigs work in coal, gold, copper, diamond and iron mines where temperatures can drop below -40C.

John Stinson

60

Atlas Copco has designed a series of heater packages for lubricants, the engine block and batteries.

Watermist closed.

Watermist open.

Proheat closed.

Proheat open.

Wiggins closed.

Wiggins open.


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The new mid range Pit Viper 235 The star of MINExpo 2008 The new ultra class haul trucks in the Central Hall arguably may have achieved the greatest visual impact at MINExpo 2008, but surface mine drillers attending the record-breaking Las Vegas show hailed their own new star in the Nor th Hall – the Atlas Copco Drilling Solutions Pit Viper PV-235 at the Atlas Copco display. This PV-230 class machine thus followed in the tracks of the first Pit Viper model, the PV-351, which was launched at MINExpo 2000, and the PV-270 series models introduced at MINExpo 2004.

Efficiency and productivity The Pit Viper 235 has a weight on bit of up to 65,000 pounds (29,500 kg) and is designed for rotary or downhole (DTH) drilling of 6-inch to 9 ⅞- inch (152 – 251 mm) diameter holes. Competitive performance and excellent long-term reliability have been key marketing points for the Atlas Copco Drilling Solutions range of drilling rigs for a long time. The PV-235 is specified and fabricated to maintain this reputation, with particular attention having been paid to the reduction of horsepower demand and non-drilling time. The cab and control technology have been significantly upgraded and the diesel engine options are Tier II and Tier III units. Atlas Copco Drilling Solutions has again placed great emphasis on flexibility in application, and the PV-235 is available with any one of three towers to drill 30-foot (9.1 m), 35-foot (10.7 m) or 40-foot (12.2 m) clean 230-mm holes. The new machine can be configured in a surprising number of ways to offer an optimal match to a mine’s particular operating method and environment. Like the PV-351 and the PV-270 models, the PV-235 will be available with either a choice of diesel engines or an electric motor. And it retains the Blasthole Drilling in Open Pit Mining

Pit Viper 235 is capable of dilling a single pass 40 ft clean hole.

hydraulic systems, including the rotary head, that have consistently been preferred by the Atlas Copco design and engineering team for many years.

Less mass, more options Starting at ground level, the Pit Viper 235 has a newly designed platform. It is built with two-speed hydraulic excavator style Caterpillar 330 undercarriages – the 330L for units with the 30-foot tower and with the 35-foot

tower, and 330EL when the 40-foot tower is fitted. The dimensions for the PV-235 version with tower up is 34 feet 2 inches long and 14 feet 6 inches wide (10.4 x 4.4 m) A high speed lock-up operates with the tower raised. The plate steel frame is new to blasthole drill construction and was designed using finite element analysis. The material thickness is one third that of an equivalent welded plate construction and has a better fatigue life. The frame accommodates the 450- and 600-gallon 61

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The enclosure option will reduce noise and provide cold weather protection; full-length doors offer easy service access.

The hydraulic automatic cable tensioning cylinder is a time saver for maintenance .

For angle drilling the PV-235 uses a pivot at the base of the tower with adjustments from vertical to 30 degrees in 5-degree increments, while keeping the deck level.

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fuel and water tanks, which are ISO block, three-point isolation mounted. An additional 400-gallon water deck tank can be fitted if no dust collector is used. For safer, easier and quicker trouble shooting and maintenance, the Grip Strut open mesh deck provides excellent access to the superstructure elements, including ground level battery and starter isolators, deck level access for the service points on most systems, and quick fills at waist level. An optional bolt-on drum deck on the drill end adds extra space for lube and other fluids storage tanks, and cleans up the deck area to allow 300° of access and improved serviceability. Other optional fittings include a central lubrication system, fire suppression equipment, a jump start receptacle and a spring-assisted ladder. For mounting on this platform, Atlas Copco Drilling Solutions has decided to offer customers a wider choice of power system options than on previous models. The structure is similar to that designed for the Pit Viper 351, with an independent sub-structure and three-point mounting. But there is a wider choice of Cummins or Caterpillar engines, covering the range 540 – 800 hp at 1,800 rpm with the Cummins QSX 15 to QSK 19 or Cat C15 to C27 engines, all meeting Tier III regulations. There is also a wider choice of air compressors, as either single-stage asymmetrical oil flooded Atlas Copco or Ingersoll-Rand rotary screw units are available for low pressure (1,200 – 1,900 CFM, 100 psi) rotary drilling, and the two-stage equivalents for high pressure (1,250 or 1,450 CFM, 350 psi) downhole drilling. A new Electronic Air Regulation System (EARS) allows low load starting. The hydraulic system has been further refined with load sensing and other features to reduce horsepower demand. The heavy duty Funk gearbox is driven by a drive shaft from the front of the engine. There is one piston pump for rotation; one load sensing piston pump for the feed, set-up and auxiliary functions; and one pressure-compensated piston pump for the fan circuit. The propel function uses the feed and rotation pumps and there is an in-cab Blasthole Drilling in Open Pit Mining

Talking Technically

switch to select the diverter valves. The valve rack is centrally located for easy service access, at the same time simplifying hose runs and control wiring. The pressurized hydraulic fluid tank has a capacity of over 100 gallons and the filters are serviced at waist level. To allow operation at ambient temperatures up to 125° F (52° C) the cooling system features oversized radiators. Variable speed control helps to reduce fuel consumption and noise and improves cold weather performance. The low fan speed also lowers noise emissions. Available as an option is a very smart enclosure that further reduces noise, provides cold weather protection and has full length doors for service access.

Towers The open front structure of the three towers available is similar to that used on the other Pit Viper models – fabricated from rectangular steel tubing by certified welders and having four main vertical members. The 40-foot (12.2 m), 35-foot (10.7 m) and 30-foot (9.1 m) hole depths mentioned previously are the distance from ground level to the bottom of the hole, while the top of the bit basket is 5 feet above ground level. Using a starter rod and the updated four-rod carousel, the 40-foot tower can be used to multi-pass drill to a maximum depth of 200 feet (61 m). The carousel features a spur indexing drive and a parking brake. The PV-235 is fitted with a standard single-speed direct drive rotary head that requires less maintenance than other designs. Operating at 0 – 130 rpm this unit provides a torque of 7,800 lbf-ft (10.6 kNm) while the 200 rpm option delivers 5,200 lbf-ft (7.0 kNm) of torque. Alternatively there is an optional twospeed head delivering either 4,250 lbf-ft (5.7 kNm) at 200 rpm, or 8,800 lbf-ft (11.9 knm) at 100 rpm. These rotary heads are fitted with adjustable wear guides. The spur gear head design used on the present DM45 and DML rigs is an option. The single cylinder cable feed designed for the PV-235’s 40-foot tower provides a hydraulic pulldown force of 60,000 pounds and a further improvement in non-drilling speeds. The sheave diameter: cable diameter (D/d) ratio Blasthole Drilling in Open Pit Mining

The RCS option provides various levels of automation.

is 22:1 and reverse bending of the cables, which can create excess fatigue and shorten cable life, is eliminated. The pull-down rate is 140 ft./min. with the 40-foot tower and 193 ft./min. for the 35and 30-foot towers. Retract is 202 ft./ min. with the longest tower and 195 ft. /min. for the other two. Auto-tensioning of the cable, necessary to counter the loss of tension caused by cable stretch, is by means of a single cylinder with exclusive balancing yoke. For angle drilling the PV-235 uses a pivot at the base of the rig tower, proven on the earlier Pit Vipers, with adjustment from vertical to 30° in 5-degree increments. But the rear telescopic support legs provided on the larger rigs are unnecessary. This single pivot design reduces non-drilling time significantly, with tower raising and lowering improved. The rig has a new twocylinder impact slide wrench for drill string breakout that has replaced the single-cylinder deck fork used on previous models. The rear jacks are

incorporated into the new tower rest, as are the exhaust mounts, air cleaners and lights. The arch-shaped rest adds torsional stiffness to the frame and riser arms secure the tower when it has been lowered, reducing wear during tramming.

Even better cab Together with the power system enclosure, if fitted, the most distinctive feature of the latest Pit Viper is the cab. The cantilevered pod-type FOPS design is a further advance on the progress achieved with the PV-270 series machines in terms of both capabilities and appearance. Visibility is enhanced not only by the shape of the cab and large glass area, but also by tinted windows, improved wiper/washers and six Nordic integral lights (which also consume less power than conventional ones). The integrated air conditioning system - with hydraulically powered compressor, evaporator and condenser 63

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The FOPS designed cab offers excellent visibility and comfort.

– is mounted under the cab rather than on the side. The Atlas Copco engineers worked with the cab supplier to achieve further noise reduction. For easier “housekeeping” there are fitted floor mats and a sweep-out door at the nondrill end. Optional offers are a safety camera system and a radio/CD player for the cab. The standard controls are electric over hydraulic, with push buttons and in-seat joysticks – one for each hand – operating the key drilling and tramming functions. Adding the proven Atlas Copco RCS computerized network rig control system, which is an option, provides various levels of automation, in common with the rigs manufactu-red by the company’s surface and underground teams in Sweden. For the PV-235 these options include remote tramming, auto leveling and GPS navigation, all 64

A two speed excavator style undercarriage.

of which can help minimize non-drilling time, and also measure-while drilling logging technology. (See page 25 for RCS explanation.) Prospects for the new Atlas Copco Drilling Solutions model are good

if the Pit Viper 235 enjoys the same level of success as its predecessors.

Dustin Penn


Talking Technically

Development through interaction Single- or multi-pass drilling The medium scale Pit Viper 270 series drilling rigs provide 75,000 lbf (340 kN) force on bit and can be equipped for either rotary or downhole (DTH) drilling. They combine structural features of the PV-351, components successfully used on the DM45, DM-M2 and DM-M3 models, and some new ones, including Tier II engine options. These features were incorporated as a result of extensive discussions with customers already using the Drilling Solutions equipment range and with other professionals interested in the application of the Pit Viper concept at this scale of rig.

Low center of gravity Clearly an essential quality for this market is f lexibility, though the design engineering team could not ignore the across-the-board industry requirement for maintenance convenience and cost effectiveness. These two characteristics are evident from the PV-270 crawler tracks through to the choice of singlepass or multi-pass drilling. The PV-270 machines offer a choice of proven Caterpillar and Atlas Copco undercarriages to enhance their compatibility with other mine fleet members. The PV-271 is built with the extended version of either the CAT 345SL or the Atlas Copco GT3400, while the PV-275 can have either the standard 19-foot 6-inch (5.9 m) CAT 345SL with GFT110 final drive or the ACGT 3400 tracks, with two-year track and 30,000hour side frame warranty. The design and testing process used for the PV-270 main frame was generally similar to that for the Pit Viper 351. To ensure long frame life without rebuilds, the I-beam used is 24 inches thick with a cross section of 162 lb./ ft. – smaller than the PV-351 frame but almost twice the size used on the DM-M3 rig. The structure achieves a low center of gravity for good stability Blasthole Drilling in Open Pit Mining

Pit Viper 275 used for blasthole drilling in South African coal mine.

and reduces drilling vibration.Singlepass stability ratings, adjusted for dynamic conditions, are 5° with cab facing downhill and 8° tramming across the slope, both with tower up, and 10° with tower down, cab facing uphill. The equivalent multi-pass figures are respectively 11°, 13°, and 16°. The rigs also offer the customer a choice between a standard three jack configuration and four, with the rear jacks tied as on the Pit Viper 351.

Power options The power system setup for the PV-270 series machines is structurally similar to that on the Pit Viper 351 but includes a choice of matched engines and compressors suitable for the rotary or downhole drilling options. The engines offered, which are Tier II compliant, are the 760 hp (567 kW) Cummins QSK 19, the 800 hp (597 kW) Caterpillar C27, and the larger 950 hp (709 kW) Caterpillar C32. There is a single side-by-side hydraulic/compressor/radiator cooler package. The Ingersoll-Rand compressor options are a 1,900 CFM (900 l/s) unit or a 2,600 CFM (1230 l/s) supplying 110 psi (760 kPa), plus a 1,450 CFM (680 l/s) air compressor delivering air at 350psi

(2,400 kPa) for downhole drilling. The CAT C32 engine is fitted on those rigs using the 2,600 CFM compressor. A lot of customers prefer the combination of CAT undercarriage and CAT engine for easily organized and reliable dealer support. The electric power pack option comprises alternatively a 700 hp (520 kW) WEG 6808 motor running on 6,000 V AC/50 Hz current and coupled with an 1,800 CFM/50Hz Ingersoll-Rand air compressor, or a 900 hp (671 kW) WEG 6811 motor running on 4,160 V AC/60 Hz power that is coupled to the Ingersoll-Rand 2,600 CFM/60 Hz air compressor. An electric powered version for downhole drilling is available for the DM-L rig, and a similar unit could be developed, if required, for the PV-270 machines, albeit limited to 1,070 CFM and 350 psi for 50 Hz application. The motor is totally enclosed and is cooled by a fan with the highest rating in the industry, which allows the unit to operate without a machinery house. An oil-immersed non-flammable 40 kVA transformer protects the motor, providing 380 V AC for the extensive heating package used for all the reservoirs. The high voltage safety circuit and the operator controls run on 110 V AC that is converted to 24 V DC so that 65

Talking Technically

The PV-275 can be used for angle drilling with 0 - 30° adjustment in 5° increments. Photo from an Australian coal mine.

the electric machine can use the same components as the diesel-driven rigs. Experience shows that electric motors typically last 20,000 – 30,000 hours before replacement or rebuild in this application, as compared with the 10,000 – 14,000 hour life usually attained by diesel engines. This is one reason why there is growing interest in the electric Pit Vipers, to which Atlas Copco has also responded by matching the electric power pack to a mine’s available power supply. For example, four PV-275 rigs have been delivered to the Moroccan phosphates producer Office Chérifien des Phosphates (OCP) for operation at 5,500 V AC. Like that on the PV-351, the hydraulic system for the 270 series utilizes a leak-free, clean specification. However it has the single gearbox and three pumps configuration used on the DM-M3 rig, albeit with larger units; using fewer components has proved to reduce operating cost. There are two main pumps for feed, rotation and propel, while the double pump supplies the auxiliary functions. The air cleaners are similar to those on the PV-351, with one provided for the Cummins engine, two for the CAT, one for the 1,900 CFM air compressor and two for the 2,600 CFM unit. These and the other serviced units are easily accessed from the PV-270 deck, which is designed on similar lines to that of the PV-351, while retractable ladders are also available.

Three towers

The PV-271 live tower is dimensioned for 55-foot single-pass drilling, there is also a 65-foot clean hole single pass drilling tower option where the rotary head and tower has to be down when moving the drill rig.

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The two machines comprising the Pit Viper 270 series are primarily differentiated by their towers. These are of similar construction to those on the PV-351 but are new designs, not stretched or lighter weight versions of the existing design. The PV-271 live tower is dimensioned for 55-foot (16.7 m) clean hole single-pass drilling. Like the PV-351 it does have a two-rod changer, in this case for 25-foot rods enabling drilling to a total depth of 105 feet. With a fourrod carousel holding 40-foot pipe, the PV-275 is designed for multi-pass drilling to a maximum depth of 195 feet. There is also a 65-foot clean hole tower Blasthole Drilling in Open Pit Mining

Talking Technically

The PV-271 Rotary head.

option, but with this unit one drill pipe must be racked and the rotary head brought down in order to lower the tower for relocation. Like the power pack, the variable displacement rotary head for the PV-270 rigs is very similar to the proven design used on the DM-M2 machine. Equipped with two motors the 188 hp (252 kW) rotary head delivers up to 8,700 foot pounds (11.8 kNm) of torque. Maximum speed is 150 rpm. Internal spur gear speed reduction gives better torque on rough ground and in other circumstances where the head stalls later than other designs. The hydraulic rod support with automatic actuation is essentially the same as that proven on the DM-M3 rig. There is also an upper fixed rod catcher. Again like the PV-351, the Pit Viper 270 series drilling rigs use the cable feed system introduced on the DM-M3, however with some redesign to achieve Blasthole Drilling in Open Pit Mining

The Pit Viper 271 cab offers the operator excellent visibility and the sound damping has been tested down to 70 dB(A).

faster feed speeds. The feed rate is 127 ft. /min. (38 m./min.) and the retract rate is 158 ft./min. (48 m./min.). The automatic tensioning is derived from the PV-351 system which has proved problem-free to date. The pipe handling system on the PV-271 is similar to that on the PV-351, and the PV-275 is similar to the DM-M3. The PV-270 series machines also use the same patented system for angle drilling as the Pit Viper 351, with 0 - 30° adjustment in 5° increments for the multi-pass PV-275 and 0 - 20° adjustment in 5° increments for the single pass PV-271. These rigs are quite widely used for angle drilling, both in coal mines and in metal mines for toe blasting.

piece design as that used for concurrent DM45 and DM-L machines. It meets the FOPS requirements of ISO 3449 Level 2, is thermally insulated and pressurized, and has adjustable vents for climate control. The air conditioning unit is side mounted, which, along with other detailed features, makes this cab easier to service so no roof access is required. The sound damping has been tested down to 70 dB(A). The operator enjoys excellent visibility over the ergonomically designed wrap-around console. The controls are predominantly electric-over-hydraulic sticks.

Cab commonality

As well as the four jack system, options available for the PV-270 series rigs when they were introduced included a dry dust collector with 9,000 CFM blower,

The cab fitted to the Pit Viper 270 series rigs is essentially the same single

Options

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four-camera system with LCD monitor, buddy seat, water injection, fire suppression, cold weather package, a central fast service system, high intensity Nordic lights, and a hydraulic test station (that is now standard) and many more options. A new option is the Atlas Copco computerized RCS control system (See article page 25.) Several PV-270 machines have been delivered with RCS.

Rapid acceptance The Pit Viper 270 series rigs were rapidly accepted. It was a machine that got it right in terms of all the parts working together perfectly, and customers seem to agree. In only four years the sales of the PV-270 series surpassed the accumulated 14-year sales record of its predecessor, the DM-M2. Barrick was one of the first mines to use a PV-271 at their Goldstrike operations, and the company now has nine of them. Newmont was another early customer, buying four PV-271 machines for the Yanacocha gold mine in Peru, and now has 17 of these rigs. Copper mining customers include Freeport-McMoRan which now has over 20 machines. Most recently, the PV-270 series has broken into the Australasian coal and metals markets. Many of the PV- 270 series rigs have been ordered for coal applications mainly in South Africa, Russia and the USA. The other major applications are in copper and gold, mostly in the Americas, and iron ore mines in Africa, Latin America, Russia and Ukraine. Almost all of the PV-275 machines are equipped for rotary drilling, but a significant number of the PV-271 units have ben configured for downhole drilling, mainly single-pass drilling of 8-inch diameter holes at gold mines. Since the first PV-275 was shipped for testing at Peabody’s Kayenta coal mine in 2003 and the 2004 MINExpo launch of the new models, more than one hundred fifty PV-270 series rigs have been shipped to customers.

Dustin Penn

PV-271 working in copper mine.

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Large diameter drilling Pit Viper 351 The giant Pit Viper 351 is a flexible rotary drill rig with a weight on bit of 125,000 pounds (56,700 kg), and the ability to drill 10 5/8 -inch to 16-inch (270-406 mm) diameter holes to a maximum depth of 135 feet. However, at MINExpo 2000 many customers commented: “It’s set up to single-pass drill a 65-foot-deep hole.” The PV-351 is ruggedly constructed with an operating weight of 385,000415,000 pounds (175-188 tons). However, it takes only touch screen controls and a joystick to operate.

Power platform From the ground up, the Pit Viper 351 is a robust and highly capable drilling rig. The undercarriage is a hydraulically driven custom version of the Caterpillar 385 excavator unit. At 26 feet 10 inches (8.18 m) in length this is the largest undercarriage used for a rotary drilling rig. Maximum tramming speed is 1.1 mph (1.77 km/h). The main frame was designed using finite element analysis and was subjected to dynamic strain gauge testing. To ensure long frame life without rebuilds, the I-beam used is 30-inches thick with a cross section of 326 lbs./ft. It supports three inboard mounted tanks – one 900 gallon (3407 liter) water and two 600 gallon (227 l) fuel – as well as the forward jacks and rear tower support and jacks assembly. There are four levelling jacks with 10-inch (254 mm) bore and 72-inch (1829 mm) stroke. The rear jacks are cross linked to minimize frame twisting. Power for the multiple hydraulic systems and air compressor used on the Pit Viper 351 comes from either a diesel engine or an electric motor. Either drives the hydraulic power pack via a drive shaft and the air compressor directly. A floating power pack sub-base isolates the components from vibration. Two coolers allow operation up to an Blasthole Drilling in Open Pit Mining

The diesel powered PV-351 can be offered with Cummins or CAT 12-cylinder engines.

ambient temperature of 125°F (52°C). Two 12-cylinder diesel engines with electronic monitoring systems that meet the EPA Tier I standard are offered – the Cummins QSK 45, rated 1500 hp (1119 kW) at 1800 rpm, and the

Caterpillar 3512, rated at 1650 hp (1230 kW) at 1800 rpm. The 1400 hp (1044 kW) electric power unit comes with a rear access platform and, optionally, a 1500-foot (457 m) capacity cable reel for 2-inch (51 mm) 69

Talking Technically

Pit Viper 351 “live” tower.

Weg motor – 1400 hp.

cable. The WEG 6811 squirrel cage motor normally runs on a 50 or 60 Hz, 4160 – 7200 V AC power supply. The machinery house for the electric unit, containing the majority of the main components, is hydraulically pressurized and has two access doors and removable roof panels. Some 80–85 percent of the components used in the rig are the same in the diesel and the electric versions. The hydraulic system has a 350 gallon (1325 l) tank with three-micron filtration. To ensure reliable operation, the designers made extensive use of hard piping with Stauff clamps for hoses, O-ring face seal fittings and two quick change filters. There is a single gearbox and five pumps. The main Parker Denison variable displacement pumps control the propel motors and drill feed/ rotation. Other pumps run various auxiliary functions. The use of integrated circuit blocks reduces the number of hose connections. The well-proven Ingersoll-Rand asymmetrical screw compressor features twin rotors in parallel, variable volume electronic control and lubrication pumps that minimize load during startup. It delivers up to 3,800 CFM (107.6 m 3/ minute) of air – the highest rate ever available on a blasthole drill – at 110 psi (758 kPa), a pressure that ensures improved bit life. The air cleaners employ an innovative three-stage system in which the elements are easy to access and easy to change. Quick release covers make for easy operator maintenance. The Pit Viper 351 is designed to be a maintenance friendly machine. The superstructure is laid out to allow safe, easy movement and good access to service points. The rig has standard Wiggins Quick Fills for programmed maintenance and daily refilling. The spool valves are located above the deck and all the filter elements are easy to reach. The standard decking to the rear of the tower and the tower access ladder enable service personnel to inspect the rotary head and other tower components while the tower is down.

Versatile tower Valve stand offering excellent accessibility for maintenance.

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Like the main frame, the tower for the Pit Viper 351 was designed with the aid

of finite element analysis and tested by dynamic strain testing. The tower is of open front construction, fabricated by certified Drilling Solutions welders using rectangular steel tubing, and has four main vertical members. The design retains the unique “live” design used for the Drillmaster towers, which enables the operator to raise and lower the tower with the rotary head at the top and the rods in place, a capability that typically saves 4 – 10 hours work when moving a rig. The tower is dimensioned for drilling 65 feet (19.8 m) in a single pass. Using a longer starter rod, the operator can drill 70 feet (21.3 m) in a single pass but the tower cannot be used live. There is also a two-rod carousel with key lock retention for 35-foot (10.7 m) long and 8⅝-inch to 13⅜-inch (219 – 340 mm) diameter drill pipe so the PV-351 can to drill to a depth of 135 feet. Drill rotation uses the hydraulic drive rotary head system that the Garland team has preferred to an electric motor drive for a long time. It is the compact size and light weight of this design that makes possible “live” tower operation of the PV-351 and preceding Drillmaster rigs. The variable displacement rotary head on the big Pit Viper has two 14cubic-inch motors that deliver 340 hp (254 kW) and a maximum torque of 19,000 foot-pounds (25,759 Nm). Maximum speed is 170 rpm. Simply adjusted extended head guides maintain alignment during descent and a separate lube pump improves motor spline life. A rod support system, actuated automatically by detection points at the rotary head, supports the pipe at its mid-point whenever the rotary head is near to the top of the tower. Another important feature of the Atlas Copco Drilling Solutions rig design is the patented cable feed pull-down and pull-back system developed inhouse and introduced on the DM-M3. It is low-cost, four times lighter and much quieter than a chain feed, but offers good buckling resistance. The cables absorb the loads transmitted by drilling before they reach the rotary head so that drilling is smoother and bit wear is reduced. As well as providing 120,000 pounds (54,446 kg) of pulldown and 125,000 pounds (56,700 kg) of bit load, the dual Blasthole Drilling in Open Pit Mining

Talking Technically

Comfortable cabin with excellent visibility.

Automatic cable tensioning – pull-down cables jack screws.

The optional cable reel for 1600 feet of 2-inch cable.

cylinder system delivers 70,000 pounds (31,752 kg) of pull-back and retract speed is 140 FPM (42.7 m/min). The system also improves rig safety as the operator can detect dangerous amounts of wear, whereas a chain feed can fail catastrophically. The downside is that stretching in use results in a loss of cable tension, but this has been countered by an automatic tensioning system that uses independent hydraulic motors and jack screws to tension the pull-down cables and hydraulic cylinders to tension the pull-back ones. The system maintains tension, ensuring accurate rotary head alignment, and eliminates maintenance hours for tensioning. The break-out system may not be the most technically sophisticated piece of equipment on a rotary drilling rig, but from the operator’s point of view, its effectiveness is very important in terms of the physical effort required and the non-drilling time involved. On the Pit Viper 351 primary break-out is achieved simply and effectively by a sliding fork and reverse rotation. A patented self-adjusting hydraulic tong wrench, already proven on the

DM-M3 rigs, is used for auxiliary break-out. Neither operation transmits shock loads to the tower. The PV-351 has a patented system for angle drilling between vertical and 30°, in 5° increments. The same system is used on the DM-M3 rig. There is a short, independently supported pivot point and hydraulic cylinder at the base of the tower, and two telescoping rear legs are attached to the tower close to the rotary head’s uppermost position and to the tower rest at the rear of the rig. Locking pins are remotely activated. This configuration allows the tower to pivot at deck level, minimizes the amount of unsupported drill pipe, and gives the operator a better view of the deck. The hole to be drilled can be collared within the Pit Viper’s dust hood.


New generation cab The operator’s cab designed for the PV-351 represented a major step forward for rotary drilling rigs. Structurally it incorporates FOPS protection meeting the ISO 3449 Level 2 standards, floormounted air conditioning with adjustable

vents, and sound damping to 75 dB(A). The cab is raised to improve forward visibility and provides a good direct view of the rig deck as well. The windscreen has wiper/washers as standard; there is a pressurizer, and sun shades are optional. The operator’s ability to maintain high productivity through a shift is further enhanced by an adjustable, swiveling suspension seat that is optimally placed for using the touch screen machine interface and the multi-function stick controls for feed, rotation, propel, and tower raising. The sticks for jack operation and tramming have safety triggers. Auxiliary functions are push-button operated. The Pit Viper 351 has a control system that utilizes five computers and provides integrated drill technology options. It was designed to work with the GLOBAL positioning and monitoring system and to provide a platform for future automation. The rugged infrared touch screen displays data from the rig’s central computer, including all pertinent drill information, using internationally recognizable symbols. The screen is not affected by dirt and can be used by 71

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Operators panel with the RCS touch screen.

operators wearing gloves. The PV-351 rigs being supplied to Boliden’s Aitik copper mine in Sweden are equipped for Remote Rig Access, enabling Atlas Copco to check the drilling performance, maintenance requirements, etc. from distant locations. Aitik already uses this technology to good effect for other major equipment units. This includes the RCS (computerized Rig Control System page 25), GPS positioning, MWD (Measurement While Drilling) data collection functionality, Autodrill, Auto levelling and wireless data transfer.

Options A number of equipment options are available for all the Pit Viper models. These include fire suppression systems and computer-controlled central lubrication. Specific options developed for the PV-351 include a cold weather package for operation in ambient temperatures down to -40° C, a four-camera LCD vision system and attention horn, and a wireless remote propel control. Remote controlled tramming with the operator off the rig is mandatory in certain situations under some regulatory authorities. Additional options are a Hiab crane 72

for loading and unloading bits and accessories, hydraulic retractable staircase, tower ladder and much more. Optional equipment for electric Pit Vipers includes a 5-by-8-foot cable reel for 1,600 feet of 2-inch cable, a load break switch, a power factor correction system, a machinery house pressurizer, and a 2,100 gal (7,950 l) water injection system.

Extensive experience It is now almost eight years since the first Pit Viper 351 started drilling at the then Phelps Dodge Morenci copper mine. This prototype machine has now operated for more than 40,000 hours. A second field follow machine went to Northgate’s Kemess mine in May 2003. Atlas Copco decided to invest considerable amounts in production facilities, and this enabled the Drilling Solutions division to step up marketing efforts as mining industry investment in new equipment began to increase. Commercial deliveries of the Pit Viper started in 2005-6 and the first PV-351 units headed south to Codelco’s Chuquicamata copper mine in Chile and to the Anglo Platinum Potgietersrust operation (now called Mogalakwena) in

Excellent view of the drill deck from the cabin.

South Africa. Codelco reported excellent results with the first machine and ordered a second rig that arrived at Chuqui in September 2006. Soon after, another PV-351 started operating at Codelco’s Radomiro Tomic mine and Andina or-dered electric powered machines. The first two Pit Viper 351 rigs at Anglo Platinum now have a fleet of nine electric machines. There are now PV-351 fleets working for Vale at Sossego in Brazil, at the Penasquito precious metals mine in Mexico, and at the Los Pelambres and Spence copper mines in Chile. Antofagasta chose a mix of diesel and electric rigs for Los Pelambres and Rio Tinto has done the same at the Rössing uranium mine in Namibia, southern Africa. Antofagasta minerals has ordered electric PV-351 units for its Esperanza project in Chile, while a fleet of PV-351s entered service in Western Europe at Boliden’s expanding Aitik copper mine in northern Sweden.

Dustin Penn


Talking Technically

Peace of mind Focus on uptime A large and growing number of customers count on the economic advantages of involving Atlas Copco in the servicing of their equipment throughout its operational life. They know that qualified service and maintenance are the most important factors in maximizing efficiency and minimizing downtime. Atlas Copco continues to harness technology and improve skills to deliver comprehensive parts and services to meet those needs.

The DRILLCare portfolio Developing valuable service and maintenance programs that provide high quality care for customers using new Pit Viper and other drilling rig models around the world has involved a number of key steps: • alignment with a proven, traditional approach to parts and service provisioning already practiced within the Atlas Copco group; • taking into account the global spread of the drilling rig fleet; • achieving the highest possible level of competence within Atlas Copco Customer Service Centers around the world; • providing top quality materials, parts, services and documentation necessary for optimal drilling rig operation and maintenance; and • state-of-the art distribution center. Atlas Copco Drilling Solutions parts and services team has built a customer care program for direct delivery to the mine site. The DRILLCare™ program is designed to ensure continued reliability and highest possible availability of drilling equipment, yielding to the customer superior productivity and the lowest total cost of ownership. Every element in the DRILLCare™ portfolio of products and services was designed and launched with customer care in mind. Blasthole Drilling in Open Pit Mining

Atlas Copco DRILLCare TM is designed with customer care in mind. For more information go to: www.atlascopco.com/drillcare

• • • • •

DRILLCare Genuine Parts DRILLCare Oils & Lubricants DRILLCare Extended Warranty DRILLCare Service Agreements DRILLCare Innovative Solutions

Genuine parts DRILLCare™ Genuine Parts are manufactured to the same quality standards as the components used for drill rig manufacture. They undergo the same endurance testing and quality assurance process. Consequently, these parts are warranted between scheduled machine services and will maintain the reliability, availability and performance of the drilling rig. In addition to individual parts, Atlas Copco Drilling Solutions packages comprehensive service kits containing all required components for specific tasks. The prices for these kits are always more favorable compared to the individual component costs; they reduce inventory size and administration as well as

minimize service time. To support customer needs, our 129,000-square-foot climate controlled distribution center in Allen, Texas, processes and ships over 1,000 line items daily. The facility is staffed by more than 75 dedicated employees ensuring quick, accurate order fulfilment to a 24/7 global drilling fleet.

Oils & lubricants Formulated by specialist suppliers to exacting Atlas Copco Drilling Solutions specifications, the DRILLCare™ range of oils and lubricants are, like the genuine parts, subject to rigorous quality assurance procedures. Their use ensures extended warranty eligibility as well as helps to minimize downtime and optimize service life.

Extended warranty Designed to offer additional protection against unscheduled component failure 73

Talking Technically

downtime and they help customers achieve lowest total operating cost for their drilling equipment.

Innovative solutions

Hydraulic Hose First Aid Kit - Provides an immediate replacement for every hydraulic hose on our drill rig.

for a three-year period with unlimited operating hours, the DRILLCare™ Extended Warranty offers fair, simple coverage with no small print. It covers the air compressor, rotary head, hydraulic pumps and motors, hydraulic feed and jack cylinders, main frame and tower, and Atlas Copco approved undercarriage. To meet warranty conditions, the customer is responsible for following the Atlas Copco service schedule and planned audits, and must use genuine parts, selected oils and lubricants. Following these procedures allows the customer to focus on production while assuring rig

reliability. The extended warranty can also be linked to DRILLCare™ Service Agreements.

Service agreements Taking the quality of care up a level, DRILLCare™ Service Agreements provide customized protection plans for drilling operations. These service solutions feature total maintenance, preventative maintenance, fixed-price repair and parts-only plans. They utilize genuine Atlas Copco parts and materials so that the extended warranty period is secured. They minimize unplanned

To enhance the value of DRILLCare™, Atlas Copco continues to develop products that increase the effectiveness and efficiency of drilling and maintenance operations. In addition to premium quality air and hydraulic hoses, the company has introduced a Hydraulic Hose First Aid Kit and filter carts for both hydraulic fluid and diesel fuel. The portable, environmentally friendly Hydraulic Hose First Aid Kit contains drill rig specific hoses and adaptors with complete instructions and accessories. This enables the user to achieve a first-time fix at the job site in the fastest possible time and with spillage control. On site mobility can be increased by wheel or truck mounting. The Hydraulic Filter Cart is designed to provide a new level of fluid integrity through superior contamination control when pre-filtering new hydraulic fluids or cleaning existing systems. The threewheeled cart is highly mobile, although it can be fixed to a service vehicle or drilling rig. The unit is built with high quality components that can be configured in a number of ways. It provides multi-stage 3-micron filtration with magnetic removal of metal contaminant particles, and spin-on genuine replacement elements. There is a high pressure cut-out. Using the cart avoids the need for a contamination bypass, meets specific flow requirements and prevents secondary failures. The Hydraulic Filter Cart will improve safety and reliability, while simultaneously saving time and money. The same sturdy base unit can be configured as a high efficiency tool for diesel fuel contamination control. Atlas Copco trained service personnel shall be on-hand at mines around the world, providing support and ensuring continued operation. Their mission is to add value to every process, provide solutions and optimize each visit to help our customers improve drilling productivity.

Jeff Rose Hydraulic Filter Cart - A superior contamination control device with maximum protection in mind.

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Talking Technically

The economic case for routine bit grinding Cutting hole costs The button bit was originally developed to do the job of an insert bit, without the necessity for frequent grinding. However, it was soon found that the service life of a button bit increased considerably if the cemented carbide buttons were ground. Nowadays, it has become extremely important to grind button bits at proper intervals, in order to extend the service life of the rock drilling tool, maintain penetration rates, and drill straight holes and lower the total cost. In all rock excavation operations, the cost is usually expressed in cost per drilled metre (cost/dm), in cost per cubic metre (cost/cu m), or in cost per tonne. The cost to produce a hole depends on how fast it can be drilled, and how many tools will be consumed. The cost to produce a cubic metre of rock is dependent upon the cost of the hole, and the cost of blasting. If the blasthole is of poor quality, then more explosives will be consumed in blasting the rock. Unsharpened bits very often give a poor quality hole with deviation. Grinding constitutes around 2% of the costs of the entire drilling operation. To run the business without grinding could multiply this cost, with up to 100% added when production losses are taken into account. Labour and material are the highest costs, while the machine investment cost is low when u tilization is high, with a large number of bits to be ground.

Grinding methods There are two different methods of bit grinding to restore the buttons. The preferred method uses a diamond coated profiled wheel, and the other, a grinding cup. The profiled wheel provides a smooth and efficient grinding operation, which, Blasthole Drilling in Open Pit Mining

The Secoroc Grind Matic BQ2 grinding machine can handle drill bits up to 127 mm in diameter.

700

throughout its life, maintains the correct button shape and prot rusion. It features correct centring on all buttons, producing a high quality cemented carbide surface, with no risk of cemented carbide nipple. Long bit life, and higher penetration rates, will result from good grinding quality. Disadvantages of using the grinding cup are that it may produce an incorrect button shape and protrusion. It is difficult to centre the grinding cup over the gauge button, and there is also a risk of producing a sharp cemented carbide nipple on the button, and a possibility of scratches due to the larger diamond grain used. Reduced bit life will result from poor grinding quality. Several tests have been carried out to find which method gives the best bit performance. The grinding wheel gives the correct shape to the button, regardless of the amount of wear on the wheel, ensuring that the bit will achieve

Total bit life drill metres

600

10 regrindings per drill bit

500 400 300 200

Grinding interval drill metres

100 0 10

20

30

40

50

60

Diagram 1: Typical bit life grinding at different intervals.

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Talking Technically

Diagram 2: Risk of total loss when a bit is overdrilled.

standard penetration rate throughout its entire life. It has also been shown that bit life is increased considerably when grinding wheels are used, rather than grinding cups. Wheels also excavate steel around the button, simplifying the grinding task, and giving the bit a more exact profile.

Bit life With so many parameters involved, it is difficult to estimate bit service life. First, a proper grinding interval must be established, preferably at the stage when the button has a wear flat of one third of the button diameter. When

the number of drilled metres to reach this stage has been established, then a calculation of bit life can be made, by multiplying by the number of times it can be reground. As a general rule, a bit can be reground 10 times, but smaller bits may achieve slightly less than this figure, while larger bits may achieve more. So, if the grinding interval has been established as 60 drill metres, then the average bit life will be 660 drill metres (diagram 1). If a bit is overdrilled, and the wear flat is more than half of the button diameter, there is a tendency towards cracked buttons. There is always a sharp edge created on the button, and this becomes sharper the more the bit is overdrilled. This sharp edge, especia lly on ballistic buttons, is very brittle. Once the edge cracks, pieces of cemented carbide break away and circulate in the hole, causing secondary damage to the buttons. When a bit doesn’t show any vis ible wear flat, it may be suffering from micro cracks on the cemented carbide surface. This is known colloquially as snakeskin, and can be clearly seen when using a magnifier. In this case, the surface has to be ground away, otherwise the micro cracks lead to more severe damage on the buttons. Likewise, buttons which protrude too much must be ground down to avoid damage (diagram 2).

Penetration rate

Diagram 3: Penetration rate drops as the button profiles flatten.

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When the right bit has been chosen for the rock condition, it will provide maximum penetration rate, along with acceptable hole straightness. In rock conditions like Swedish granite, with a compressive strength of around 2,200 bar, the bit gets a wear flat after just 10-20 drill metres, accompanied by a small drop in penetration rate. When it has a wear flat equivalent to one-third of the button diameter, the penetration will have dropped by 5%. If the bit is used further until it has a two-thirds wear f lat, the penetration will have dropped more than 30% (diagram 3). When a bit has a heavy wear flat it tends to deviate, and, by the time it reaches the bottom of the hole, it will have deviated far more than planned. As a result, Blasthole Drilling in Open Pit Mining

Talking Technically

Grinding material cost

5

Machine cost

4 3 2

Annual grinding volume – buttons.

1

Figures on the left side of the diagram show cost per button in SEK.

100 000

0

75 000


Labour cost

6

50 000

Diamond grinding wheels.

7

25 000

Two parameters guide the selection of the right grinding machine: the number of bits to be ground; and whether the machine should be portable or station ary. Several kinds of grinding machines are available to satisfy these parameters. In most cases, a simple machine will suffice for a small operation, grinding only a few bits. The semi-automatic machines are more suitable for larger operations, such as mines and construction sites, where the machine can be stationary, and the rocktools can be brought to it. Secoroc Grind Matic HG is a water or air-cooled handheld machine for grinding cups. Both spherical and ballistic cups are available. The machine is driven by up

8

10 000

Grinding machines

9

5 000

the blast will produce coarse fragmentation, and much secondary blasting may be required. In slope hole drilling, it is of utmost importance that the holes are straight. If the holes deviate, the slope walls will be uneven, making rock reinforcement more difficult than expected. Rock formations with different layers and joints are often characterized by heavy hole deviation, putting extra stress on the remaining rock tools in the drillstring. A sharp bit always cuts better, and will prevent both deviation, and its disadvantages.

Cost of grinding reduces dramatically with volume.

to 7 bar compressed air, and is suitable for a small grinding operation. Secoroc Grind Matic Manual B is an air-driven portable grinder using diamond-coated grinding wheels for spherical and ballistic buttons. The machine is mounted in a box fitted with wheels and handles for easy set up. It is mainly for threaded button bits, but small down-the-hole bits can be ground in this machine. A steel spring is mounted in the profile of the grinding wheel, where it functions as a centring device, allowing for easy grinding. Secoroc Grind Matic Manual B-DTH is similar to the Secoroc Grind Matic Manual B. It is mainly intended for down-the-hole bits and COPROD, but

can also be used for threaded bits with a special bit holder. As an optional accessory, the machine can be equipped with a belt grinder for gauge grinding. Secoroc Grind Matic BQ2 is the latest semi-automatic machine, with many features such as auto-indexing device, timer control, automatic feed, and an automatic centring arm. These features, coupled to an ergonomic design, ensure high productivity, and the machine is designed to handle large volumes of threaded button bits. Cooling water is recycled after the waste product has been separated in a container. Secoroc Grind Matic BQ2-DTH is the latest grinding machine for mainly down-the-hole and COPROD bits. It

Secoroc Grind Matic Manual B.

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Talking Technically

Secoroc Grind Matic Manual B-DTH.

Secoroc Grind Matic BQ2-DTH.

can also be used for threaded bits with a special bit holder. The machine has the same features as Secoroc Grind Matic BQ2, and can grind bits up to 180 mm (7 in) diameter.

Grinding advice The Secoroc Grind Matic machine’s secret of success is that both the grinding table and the diamond grinding wheel rotate. The result is perfectly ground button surfaces, regardless of whether the buttons are spherical or ballistic. In addition, the machine’s unique diamond grinding wheel is designed to ensure even wear on its grinding surface, while still retaining its profile. This, in turn, guarantees the button shape throughout the life of the wheel. Secoroc’s advice is to use Secoroc Grind Matic grinding machines, with profiled diamond grinding wheels, for grinding button bits. It is the only solution able to consistently deliver perfectly shaped buttons on customers’ bits. Correct grinding is important for every drilling operation, particularly in these days of cost consciousness and fierce competition. It can make a world of difference to the bottom line. Comparison of grinding wheel with grinding cup.

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Bo Persson Blasthole Drilling in Open Pit Mining

Talking Technically

Secoroc Grind Matic Jazz

Secoroc Grind Matic Jazz for correct and professional grinding.

Rig mounted grinder In today’s world of professional rock drilling, where ever more powerful drill rigs and hammers are used, it has become extremely important to give the drill string all the necessary care and maintenance needed if optimum drilling productivity is to be achieved. Regrinding the cemented carbide buttons of the bit at proper intervals increases the service life of the whole drill string. This, in turn, helps maintain penetration rates, while ensuring that holes are drilled straight and true. Quick and efficient grinding of button bits in surface drilling applications, where the rig is constantly on the move from one job site to another, has been an elusive goal. However, Atlas Copco Secoroc has now come up with the solution, by developing a rigmounted semi-automatic grinder. The Secoroc Grind Matic Jazz, equipped with a profiled diamond grinding wheel, achieves the same quality of grinding onboard the rig as that previously associated with static workshop models.


Development Atlas Copco Secoroc has gained extensive knowledge and experience of regrinding large volumes of button bits with stationary grinders, such as the Secoroc Grind Matic BQ2 and Secoroc Grind Matic BQ2-DTH. These, together with previous generations of similar grinders, have all used profiled diamond grinding wheels for working on spherical and ballistic buttons. However, onboard grinding machines have always been fitted with diamond grinding cups, which have proved to be less efficient than profiled diamond grinding wheels. The new Secoroc Grind Matic Jazz grinder, which is equipped with profiled diamond grinding wheels, will consistently deliver the same perfectly shaped spherical and ballistic buttons after regrinding. This is increasingly important in relation to ballistic buttons, which are becoming more and more popular.

Secoroc Grind Matic Jazz The air-driven Secoroc Grind Matic Jazz helps optimize the performance

of the rock drill and drill string, without the bit leaving the rig. It is user friendly, is designed for economy of air consumption, and can easily be retrofitted to most rigs in current use. It is delivered with an attachment for bolting on to existing rigs, which allows the operator to fold away the grinder when not in use. It will also be available through the sales companies as an option on new Atlas Copco drill rigs. To make the grinder ready for work, it is simply a matter of hooking up the air hose, connecting the electricity, and filling up the water tank for the mist cooling. The low air consumption of the Secoroc Grind Matic Jazz makes it possible to grind bits without interrupting drilling operations. The grinder is semi-automatic, and features an automatic centring device for placing each button in the correct position under the grinding wheel. An indexing bit holder is used for the gauge buttons, and there is a handy time relay for setting grinding time. Secoroc Grind Matic Jazz is a very flexible grinder that will have a beneficial influence on drilling economy. It will grind spherical and ballistic buttons, 79

Talking Technically

Grinding instructions for button bits When to regrind

Button bits should be reground when the penetration rate drops, or if any of the cemented-carbide buttons are damaged (fractured buttons should be ground flat). It is both practical and economical to redress the buttons when the wear flat reaches about 1/3 of the diameter of the button.

Look out for “snake skin”

If microscopic fatigue cracks – so called “snake skin” – begin to appear on the cemented carbide buttons, the cracks must be ground away. In any event, bits should be reground after 300 metres of drilling at the most. This should be done even if there are no visible signs of wear and the penetration rate continues to be good. If snake-skin is not removed, the cracks will deepen and ultimately result in button fracture.

Do not grind away too much cemented carbide

Do not grind too much on the top of the buttons. Let a few millimetres of the wear flat remain on top of the button.

Always grind broken buttons flat

A drill bit can remain in service as long as the gauge buttons maintain the diameter of the bit. Fractured buttons must always be ground flat to prevent chips of cemented carbide from damaging the other buttons.

Avoid grinding the gauge

1 Gauge button anti-taper has to be removed by grinding, although excessive reduction of the bit diameter should be avoided. Leave about max 1 mm of the wear flat.

Secoroc Grind Matic Jazz can easily be set up on the drill rig, here the Grind Matic Jazz is ready for grinding.

on threaded or tapered button bits, as well as big DTH - and COPROD bits from 35 mm (13 ⁄8 in) to 254 mm (10 in) in diameter. Grinding the button bit in a professional way makes sense, because grinding accounts for only a fraction of the cost of the entire drilling operation.

When a drilling programme is carried on without correct service of the bits, drilling output and product ivity will be significantly lower, and costs may escalate.

Bo Persson

Secoroc Grind Matic Jazz

Technical Data Air pressure, maximum

7 bar (102 psi)

Air pressure, minimum

6 bar (87 psi)

Air consumption

25 l/sec

Coolant container

3l

Air tool oil consumption

1.8 cl/hour

Output, spindle motor

1 kW

Speed, spindle

15,000 rpm

Voltage

24 V

Weight, exclusive of packing

90 kg (198 lbs)

Transport dimension

800 x 500 x 700 mm

Grinding Capacity

If necessary, remove some of the bit-body steel below the gauge buttons, so that a clearance (taper) of 0.5 mm is maintained. If the flushing holes start to deform, open them up with the aid of a rotary burr or steel file.

80

Maximum distance between bit holder and grinding wheel

250 mm (9 7⁄8")

Maximum diameter of drill bit

254 mm (10")

Minimum diameter of drill bit

35 mm (13⁄8")

Minimum distance between buttons

3.5 mm ( 9⁄64")


Sweden, Copper Mining at Aitik

Boliden mines economies of scale Doubling copper output To maintain cost-effective copper production Boliden AB is undertaking the Aitik 36 project. This will double concentrator capacity at the Swedish operation and require a proportionate increase in mined ore output. Atlas Copco is supplying a fleet of four Pit Viper PV-351E drilling rigs, two of which are already operating.

Aitik 36 on track New Boliden, Sweden’s major integrated non-ferrous mining and metals producer, is the third largest copper metals supplier and the third largest zinc metals supplier in Europe. The company operates primary zinc production facilities at Kokkola in Finland and Odda in Norway, a copper smelter and refinery at Harjavalta and Pori in Finland, and the Rönnskär complex at Skelleftehamn on Sweden’s Baltic coast, which treats various concentrates and scrap to yield refined copper, lead, precious metals and zinc clinker. The largest supplier of copper concentrates to Rönnskär is Boliden’s Aitik openpit mine near Gällivare, 400 km by rail from Skelleftehamn. The Aitik 36 project is designed to keep this feed stream cost competitive. “The investment will make Aitik one of the most efficient mines in the world, and will substantially improve its competitiveness. This will, in turn, generate the preconditions for healthy profits and cash flows in the future,” says Boliden´s President and CEO Jan Johansson at the time the project was approved. When Boliden started mining at Aitik in 1968, it was one of the world’s first large, very low-grade ore copper mines to be developed in a high-wage economy. As well as utilizing the most costeffective technology available, Boliden has raised capacity on several occasions in order to contain concentrate Blasthole Drilling in Open Pit Mining

The Aitik 36 project will raise ore production from 18 Mt/y in 1998 up to 36 Mt/y by 2012. The investment will make Aitik one of the most cost-sefficient mines in the world.

production costs. Aitik 36 is by far the largest of these expansions. From an initial 2 Mt/y the company had raised ore production and treatment capacity in stages to 18 Mt/y by 1998; by 2012 the present project will take it up to 36 Mt/y. Aitik 36 involves a largely new in-pit crushing and conveying system and a completely new state-of-the-art concentrator facility that will replace the existing one after a short period of combined operation. The new facilities are scheduled to start up in 2010 and, although Boliden has reduced copper production this year in response to market conditions, the company has kept Aitik 36 on the original time track, good news for the several companies supplying and/or working on the project. There has been no major new ore discovery and this massive expansion will not necessitate development of a new mine at this stage. What mainly made the expansion feasible was a new state-ofthe-art and larger scale concentrator,

which will be able to improve the operation’s economics while treating even lower ore head grades than the 0.44 percent copper, 0.22 g/t gold and 3.61 g/t silver that Aitik milled in 2005. Helped by positive exploration results in the pit area, this new parameter tripled proven and probable reserves from 219 to 630 Mt. As of December 2006 proven ore reserves totalled 520 Mt, grading 0.29 percent copper, 0.2 g/t gold and 2.0 g/t silver, while probable reserves were 110 Mt and the overall resource stood at approximately one billion metric tons. The ore available also includes recoverable amounts of molybdenum. Boliden initiated the Aitik 36 Project in 2007. At present the open pit is 3,000 meter long, 1,100 meter wide and 405 meter deep. However, to achieve the necessary ore extraction rate, Aitik must cut back the mine boundary in a number of places, including the area where some of the office and workshop facilities are located. This, in conjunction with the 81

Boliden mines economies of scale

age of some of the machines in use at the time, has required a considerable outlay on new mining equipment. Boliden undertook a thorough evaluation of the options for this purchase program in 2007.

Switching to Atlas Copco

Boliden undertook a thorough evaluation before deciding to invest in four new Pit Viper 351E rotary drill rigs. Boliden’s criteria included the ability to drill 311 mm holes to a depth of 19 meter. In addition they looked for safety and productivity enhancing features.

82

This exercise led the Aitik mine management to increase loading and haulage capacity by buying new models from the companies that had supplied the existing fleets. But, when it came to drilling rigs, the evaluation persuaded Boliden to switch manufacturer. Like the rope shovels and the hydraulic excavators in use, the drill rigs would use the mine’s electric power supply network. In deciding how to replace the four electric drive rotary head rigs then in use with four new ones, Boliden’s criteria also included the ability to single pass drill 311-mm diameter holes to a depth of at least 19 meter. In addition, Aitik looked for good built-in safety and productivity enhancing features such as finger-tip joystick controls, programmable automatic drilling modes, GPS-based hole navigation, an operator-friendly cabin, ease of raising and lowering the tower for tramming, and the ability to drill angled holes. With an operating weight of 185 tonns and offering single-pass drilling to 19.8 meter and hole diameters from 270 - 406 mm, the electric version of the hydraulic drive rotary head Pit Viper (PV-351E) that Atlas Copco offered ticked Boliden’s boxes. This was not a new model; several of these rigs had been supplied to customers in South Africa and Chile. However, it did now have Atlas Copco’s Rig Control System technology with touch screen in-cabin display and a choice of three automatic drilling modes, plus the manufacturer’s Rig Remote Access system for maintenance problem-solving. Accesses are safe and four cameras that display different views on a screen in the cabin provide good visibility where there is no sight line. In particular the 45-foot tower can be lowered in a few minutes, enabling much quicker relocation times than some competing rigs can achieve. The up to 30-degree angle drilling option is relatively expensive Blasthole Drilling in Open Pit Mining


The PV-351 could offer features like finger-tip joystick controls, a comfortable cabin, The typical hole spacing for the PV-351E is 7 x 9 m, drilling vertical holes to a ability to drill angled holes, and ease of raising and lowering the tower for tramming. depth of 19.5 m using two 9.9 m drill pipe in a single pass.

but Aitik calculated that having it fitted to just two of the four rigs would achieve the degree of operational flexibility required. A very significant factor was that the operators participating in the different evaluation tests endorsed the joystick control system, said Patrik Gillerstedt mine manager. During 2008 Boliden and Atlas Copco started to prepare for the staged delivery of the PV-351E rigs. Technical s,upervisor Stefan Kuoppa, who has been with Atlas Copco since 2001 and is normally based at the Atlas Copco CMT Sweden branch in Kiruna, visited the ADS headquarters in Garland, Texas for intensive training on the assembly and maintenance of the rig. He moved into Aitik during November 2008. Two Boliden operators spent almost three weeks in Garland to familiarize themselves with the rig, and Atlas Copco has also trained present Boliden operators to train new ones. The first two units – the ones fitted with the angle drilling option – were delivered to the mine on several trucks, and assembly of the first Pit Viper was completed in January 2009. Kuoppa’s local Atlas Copco team worked with Aitik engineering personnel under the Blasthole Drilling in Open Pit Mining

guidance of ADS experts from Garland. Not surprisingly assembly of the second rig took a good deal less time than the first. The rigs are maintained by Aitik staff, supervised by Stefan Kuoppa who commented that they had not experienced any significant problems when working on the Pit Vipers. When we visited Aitik, Stefan Kuoppa and Emil Nyström had recently started work on the third Pit Viper with the Aitik technicians, but without any staff from the United States. The team was ready to lift the tower into place. Emil would supervise the job while Stefan went on vacation.

Hands-on experience At Aitik, Boliden divides the production drilling workload between a major Swedish contractor, NCC Roads, and its own drilling team. NCC does the presplit drilling with a fleet of Atlas Copco ROC L8 DTH rigs and Boliden does all the rotary blasthole drilling. For bench blasthole drilling the typical hole spacing is 7-by-9 metres and the rigs drill 200 – 300 holes for a blasting round designed to yield around 700,000 tons of rock. Orica is contracted

to charge each hole with about a ton of Fortis Advantage emulsion explosive. The constituents are stored in Gällivare and mixed at the mine. The explosive is delivered and charged by purpose-built truck. Drilling patterns are transmitted from the mine office to the Pit Vipers using the mine’s W-LAN network but Aitik intends soon to use the Minestar system installed in 2007-8. By early July the first PV-351E to be assembled had been working for 2,100 hours and the second for nearly 1,400 hours. Drilling with the Pit Viper is a one-person operation but the operator of a hired-in wheel loader does the cable shifting when moving between benches. As well as the Atlas Copco rig being very heavy and very large (16.4 meter long, 8.1 meter wide and 31.4 meter high with tower up), the hydraulic drives, cable feed system and rig control technology make the PV-351E quite different to operate from the rigs already in use. Nevertheless, according to driller Gerd Martinsson, the PV-351E is rather easy to handle. She has been working at Boliden since 1995, and as a drill operator for the last three years. Even more experienced is Johnny Holmlander, one of the Aitik operators 83


The drill rigs drill 200 – 300 holes for one blasting round and the penetration rate can vary between 0.4 m/min in the upper part and 0.1 m/min in the harder rock types. Orica is contracted to charge each hole with about a ton of Fortis Advantage emulsion. Drilling patterns are transmitted from the mine office to the Pit Vipers using the mine’s W-LAN network.

The Atlas Copco RCS touch screen in-cabin display.

who visited Garland for training. He has been drilling for 34 years and has worked at Aitik since 1979. We joined him in the cabin as he was about to navigate the PV-351E close to the bench edge, ready to drill Hole 72. Equipped with two 9.9 meter drill pipes and 311-mm bit, the Pit Viper was to drill 84

this hole to a depth of 19.50 meters in a single pass. Holmlander commented that more typical depths were in the 17 – 18 meter range. He explained that the rig can drill at a penetration rate of 40 cm per minute in the upper part of this bench but the rate can drop to 9-10 cm/min in the harder rock types at Aitik. The operator’s sight lines to the tower and drill table unit are good, and the automatic drilling modes work very well in consistent rock, as well as the auto leveling feature that reduces wear and tear on the machine structure. The bit diameter is around 1,000 m, he said. Meanwhile, NCC Roads, a contract driller working at the mine, ordered two new ROC L8-30 Mk II rigs, which are currently up and running at the mine, replacing older rigs. The Atlas Copco ROC L8 does not have the RCS system yet, points out Stig Fredriksson, the sales engineer based at Atlas Copco CMT Sweden branch in Luleå. But he hopes that when Aitik production is

running at 36Mt/y ore there will be more L8-30 rigs at the mine, and they will probably have the RCS-system.

Future options So far, Patrik Gillerstedt says, he is satisfied with the PV-351E rigs’ progress. Now that Aitik management and operators have a clear idea of the PV351’s capabilities and characteristics in operation, they are assessing the possible use of further technical options that are available, such as auto tramming, and teleremote control. Meanwhile, Boliden is planning development of a new supplementary open pit, Salmijârvi, a short distance southeast of the present Aitik pit.

Acknowledgements Kyran Casteel, a contributing editor for Engineering & Mining Journal and Coal Age, visited the Aitik mine in July 2009.


USA, Butte, Mt

Pit Vipers beat the chill Pit Vipers fit for cold climate The city of Butte, MT, was once one of America’s biggest mining regions. Named "the richest hill on Earth," its underground operations eventually extended to some 12,000 miles of drifts. Today it is the Continental Pit mine that dominates the landscape and, since 2005, two Pit Viper drill rigs that feed production.

The continental pit Today, many cities that saw their rise in the late 19th century offer a skyline of Victorian architecture and brick high rises, but not many also have head frames jutting out amidst their skylines. In its heyday, Butte’s population was nearly three times its current size, numbering over 100,000 inhabitants. Everyone was focused on building fortunes in a growing metals market or offering services to the mining industry. A dozen antique head frames now mark the former underground activity, like monuments to an unforgotten period of history. One of the country’s leading mining institutions, Montana Tech at the University of Montana, still keeps a decline active so tomorrow’s geologists and engineers can learn from the past. Underground mining ceased in 1975 and large scale open-pit mining began in 1955 with development of the Berkeley Pit, which closed in 1983. The Continental Pit opened in 1980 and is currently 7,320 ft long, 3,640 ft wide and 380 ft deep. Projected dimensions are 8,000 x 6,000 x 800 ft. Mining in Butte today takes on a very different look. Montana Resources bought the property from Atlantic Richfield in 1986 and reopened the Continental Pit. The company stopped mining in 2000 due to high electricity costs and resumed in 2003. From 1986 to 2006, the Continental Pit has given up 1.4 billion pounds Blasthole Drilling in Open Pit Mining

PV271's team up to quickly finish holes on a blast pattern.

85

Pit Vipers Beat the Chill

A city on a hill

From left, Gary Hayes and Clint Byington discuss outfitting the rig with tank heaters.

of copper and 163 million pounds of molybdenum from 285 million tons of milled (dry) ore. According to Wikipedia, from 1880 through 2005, the mines of the Butte district have produced more than 9.6

million tons of copper, 2.1 million tons of zinc, 1.6 million tons of manganese, 381 thousand tons of lead, 87 thousand tons of molybdenum, 715 million troy ounces of silver, and 2.9 million ounces of gold.

From the top of the west ridge, on the impressive campus of Montana Tech, one looks out to a grand view of a city that slides away to the valley below. The active Continental Pit nips at the city’s edge, cresting at the far eastern ridge. As the older Berkley Pit grew over the years and the city has shrunk in population, hundreds of homes have been sacrificed to the growth of the mine. On a daily basis, 102,000 tons of rock are mined from the pit with 52,000 tons of ore milled. To keep the three shovels and 170- and 240-ton haul trucks moving, Montana Resources uses two Atlas Copco Pit Viper Series PV271 drills, which were acquired in May of 2005 to replace four older drills. In the past Montana Resources had used electric drills, but because diesel provided mobility and convenience with no electric power cables, “the decision was made to purchase diesel drills,” says Gary Hayes, maintenance supervisor for Montana Resources mobile fleet. “They’ve done really well for us,” says Hayes. The availability for the month was at 94 percent, with year to date being 85 percent. The goal for availability is 90 percent, but staying ahead of the shovels is what counts.

Cold package

Cold package solution with heater blanket mounted on air receiver tank.

86

Because cold is an issue in Montana, the mine has had to make accommodations for the weather. Each drill is outfitted with a 40 kW generator to run the cold package, which includes heat blankets and heaters for the hydraulic tanks, batteries, separator tank …etc. The engine is kept warm when not in operation with a ProHeat system. The mine is currently in the process of routing engine exhaust through the water tanks to keep the drilling water from freezing during the winter. Previously alcohol was used as freeze protection but as costs rise, the mine wants to utilize the drill’s spent energy to keep costs down. “The key is to keep going,” says Hayes. Shutting down means heating up the system to get started again. Blasthole Drilling in Open Pit Mining


Drilling on the Continental Pit in Butte, Montana.

Growing the mine Montana Resource’s driller Brian Lankford likes operating the PV271, commenting on benefits such as how the speed of the bit can be changed and about the drill’s maneuverability. “Having no cable is a plus, but simply turning it is better with this drill,” says Lankford. “Changing the bit and bushing takes about 22 minutes with this drill. Our old drills took three hours,” explains the operator. The mine bench where this PV271 is working is seven holes wide with 22 ft x 22 ft spacing. The bench is

over a hundred yards long with holes 48 ft deep. Lankford says the rock nearest the high wall is harder, taking 28 minutes to drill the 9⅞ inch holes. But further out, holes take as few as 12 minutes to drill.

Stamina and longevity Since the drills went into production in 2005, they have had few issues. The first drill is due for a complete rebuild in December. “If you run a piece of equipment 24/7, things start wearing out,” the operator remarks. “We have had no structural issues, as of yet.”

Montana Resources works closely with their dealer, Modern Machinery, which keeps a complete supply of parts to cover any standard issue. Hayes says they really rely on Modern Machinery. “Modern has a couple guys who can walk right to a problem if there is one, and they have done a great job working with our guys to educate them on the drills,” says Hayes. “When we reopened in 2003, 70 percent of our employees were new to mining,” states Hayes. “We put six guys with Modern technicians and had classes to educate them on the maintenance and operation of the drills.” Once called the “richest hill” on Earth, mining is showing no sign of slowing around Butte. Although there are 12,000 miles of underground mine workings under Butte, it is up to Montana Resources to change the landscape of Butte, and the PV271 is a big part of that future.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 3 2007. Story and pictures by Scott Ellenbecker, Ellenbecker Communications. Brian Lankford finds the control console easy to monitor in order to make adjustments.


87


Brian Lankford takes measurements of a 9 7⁄8 -inch hole to 28 feet deep.

88


USA, Elko, Nevada

Innovation through interaction First PV-271 ever built When the Pit Viper 271 drill was developed, Atlas Copco’s engineering and marketing staff worked closely with customers to design a rig for greater efficiency when the truck and shovel mining method is used. Jim Owen works at Barrick Goldstrike Mine near Elko, NV. He is not a driller or mechanic, but his day-to-day responsibilities give him the experience to know the PV-271 better than just about anyone.

Product development Atlas Copco has a creed that is stated in most internal and external communications. “We are committed to your superior productivity through interaction and innovation.” These are not just marketing words tossed about lightly, but rather a promise of conviction to each customer. However, unlike most marketing statements recited to customers, this statement is also a reminder for employees as to why they are here and what makes Atlas Copco better. If you have looked at purchasing a PV-271, you may have met or talked with Jim Owen. Atlas Copco’s Western US district manager, Jon Torpy, said that just about every company that has purchased a PV-271 in the United States, and several outside of the US, has first visited with Jim Owen about the drill. “Jim has been a great resource for other mines dealing with similar drilling conditions.” For Barrick Goldstrike, Owen is an important part of the rig’s daily operation. Owen said, “I’m responsible for everything below the tophead: shocks, subs, steel, bits, bushings, and preventative maintenance on the drills – whatever is needed. I just keep the drills moving.” Barrick’s Goldstrike mine has four PV-271 rigs and holds claim to the first PV-271 ever built. “After 27,113 hours, two compressors and two rotary heads,” Blasthole Drilling in Open Pit Mining

After consulting with customers, Atlas Copco developed the PV-271 to meet their requirements to increase productivity in open-pit, hard rock mining.

Owen said, “it is still our best performing rig with no cracks in the tower or frame. Where it counts, all is good.” Since it arrived at the mine in 2004, the original rig has been problem free. Other than the replacement of wear items and preventative maintenance, “the first rig went to work the day it was taken off the lowboy and has been drilling ever since,” said Owen. To put that in perspective, that’s a whopping 58,856 holes for a total of 2,671,217 drill ft. Over that period of time the PV-271 has had an average penetration rate of 199 ft per hour. “The rate has stayed constant over the life of the rig, faster when starting a layback and reducing when we go deeper,” said Owen.

Owen is impressed with component life, too. On the first rig he got 10,000 hours totaling 1.2 million drilled feet on the first rotary head and so far 17,000 hours on the second rotary head. Design has had much to do with this. “I really like these drills,” said Owen, emphasizing his personal reason that, “they save me so much work!” He complimented the rig’s smooth operation stating, “It is even easier on bits because not having to add a rod, there is no air loss which sometimes results in back reaming.” One of the features that Owen really likes is the Automatic Tensioning Adjustment for the cables. “As you drill the cable stretches and slackens up. With a smaller drill you’re manually adjusting 89

Innovation through Interaction

Jim Owen, Drill Supervisor, plays an important role in the rigs' daily operation and is responsible for everything needed to keep the drills moving.

about once a month or so,” said Owen, who is glad this is not necessary with the longer cables on the PV-271. The task of manually adjusting the tension requires lowering the tower which takes time. With the automatic tensioning feature on the PV-271 the work is done automatically.

Interaction from the beginning The PV-271 was developed to increase productivity in open-pit, hard rock mining. Not only was the entire drilling process examined, but also how it fit with mining operations as a whole. To ensure they hit the mark, Atlas Copco turned to Goldstrike and worked closely with the Goldstrike operations team, which included Jim Owen. Interacting with Goldstrike and other customers during the development of the PV-271 ensured that Atlas Copco developed a drill that met the mining industry’s exact requirements, not just what they THOUGHT was required. For Goldstrike 90

that meant the drills needed op-timum footage, but they also needed to drill to the shovel’s optimum performance. “A 50-ft bench would work great for the shovel, but this size drill is perfect with a 40-ft bench,” said Owen. Increasing the footage rate was a result of completing a full hole without adding or removing drill steel. Efficiencies came with more time over the hole and reduced setup and tramming time. Goldstrike uses two 25-ft steel and one 10-ft sub for a total of 55-ft. Including the ground to rotary head space when jacked up, this gives Goldstrike the required 40 to 46 ft of clean, straight hole. Production drilling at Goldstrike is done with 9⅞- and 8¾- inch bits for trim and presplit work. Owen said, “We changed the breakout wrench because the drill was designed for 7⅝- inch pipe, but we use 7-inch pipe because it’s a better fit for the 9⅞- and 8¾- inch bits – and it’s also cheaper.” Pipe could be an expensive item but because they are not making connections, drill steel

lasts them about eight months. He said when they are finished with the pipe, there is nothing wrong with it other than its diameter is reduced. The wall thickness on the bottom of the 10-ft sub is 2½ inches for extra strength above the bit. Owen said he doesn’t know a guy who would complain about the PV-271 – including drillers and mechanics. “Mechanics can be intimidated with electronics over hydraulics, but it’s so much easier to work on. And once a guy works on it, they find it’s better, not much more difficult than the wiring on your boat trailer,” he said with a chuckle. “I have no problem bragging up the PV-271,” said Owen. “It’s faster, more reliable and the factor of safety…everything just came together on this rig.” When talking about the rate of drilling, Owen said, “I’ve seen one driller get 5,500 ft in one shift.” Today Goldstrike is all rotary drilling with a tricone bit. Owen said, “13,000 ft on a bit is not uncommon and hammer drilling isn’t necessary.” Because the rigs at Goldstrike use tricone bits, a 1900 cfm 110 psi low pressure compressor is all that is needed. Many compressor options are available on the rig, depending on the type of drilling. “Innovation through interaction” are big words describing how the PV-271 came to be. It was mostly guys who use drills sitting down with guys who make drills and saying, “We need a drill that is perfect for what we do.” For those at Barrick Goldstrike, that started with a hole size, required depth and a need to mine gold more efficiently. A couple of years ago, Goldstrike reached a milestone of 30 million ounces of gold mined. “That’s the largest gold removal from any one pit in the world and we’ve mined a couple million since then,” commented Owen. So it’s safe to say the PV-271 is doing its job.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 2 2008. Story and pictures by Scott Ellenbecker, Ellenbecker Communications.


USA, Battle Mountain, Nevada

Unforgiving ground

Biting through the hard and abrasive quartzite in the Nevada desert, the single pass Pit Viper 271 gives the Phoenix Mine a clean, 45-ft hole.

Improvement and teamwork are the keys to success at Phoenix Mine The formation in Newmont’s Phoenix Mine near Battle Mountain, NV, contains high levels of abrasive quartzite but also contains precious gold, copper, and silver. Newmont started mining operations at Phoenix (formerly Battle Mountain Gold) three years ago and the planners knew they were working with a challenging geological formation. But as it turned out, it was more challenging than anticipated.

Hammer drilling with PV-271 Mine manager Mark Evatz said, “Anything that touches Phoenix rock wears fast. The rock fights back here. The Pit Blasthole Drilling in Open Pit Mining

Viper is big and bad and can take it.” Evatz is talking about Atlas Copco’s Pit Viper 271 (PV-271) blasthole drill. Because of the hardness of the rock, drilling at Phoenix requires hammer drilling and the mine uses tough Atlas Copco TD65 hammers with 6¾-inch bits. The mine’s PV-271s are outfitted with a single 1450 cfm, 350 psi oilflooded air compressor. Phoenix has six Atlas Copco PV-271 drill rigs plus an Atlas Copco DML and a DM45 midrange blasthole rig. The mine’s goal is to keep four million tons of muck in inventory to stay ahead of the shovels and support needed operational flexibility (ore control related). Drilling efficiency has been a continuous point of improvement since operations began at the mine. The singlepass depth capability of 55 ft (16.5 m) on the PV-271 helped with that. Originally, the plans called for 20-ft bench heights, supported by 23-ft drill depths, but time spent moving from hole to hole was eating up productivity. Drilling on

that plan resulted in drilling an average of 47 ft an hour. When depths were changed to 44-ft drill depths, supporting blasting of 40-ft benches, they were able to utilize the single pass capacity of the PV-271, and performance increased to over 60 feet an hour. Although the drill depth change largely supported the improvement, other aspects of continuous improvement associated with increased knowledge of the Pit Viper drills helped as well. “We are below our budgeted drill costs,” said Evatz. “This is partially because the best cost- per- foot comes from hammer drilling when in hard rock.” Pat McAmis, maintenance planning general foreman, concurred with this. “You can try to put more drills on the bench, but space and costs don’t make that practical.” The mine focuses on maximizing blast-induced fragmentation while maintaining the integrity of the ore zones (minimal dilution). Although the crusher can handle 30-inch boulders, 91

Unforgiving ground

Single pass drill of 40-ft benches with PV-271 rigs.

McAmis said, “The goal is to maximize what you’re digging – keeping a methodical approach.” At the Phoenix mine, “drills are top priority machines and we mine to feed the mill,” said McAmis. He is pleased with the performance of the PV-271 and has no major concerns, complimenting the support from Atlas Copco and his distributor, Cate Equipment. “We’re all in it to make money and you have to be fair, but I would say we work well together.”

Day to day contact Drill operator Clinton Riddle started in mining in 1976 and has seen a lot of technology advancements over the years. “For me, things really started to change the last couple of years.” He cited that these advancements include the speed of drilling with air, computerized controls, and automation on the rigs. 92

Depending on the formation and area of the mine, Riddle said a 45-ft hole can take 5 to 45 minutes. As he drills, he watches his computer monitor, which tells him the hardness of the rock, the drilling rate, and performance statistics such as time per hole, torque and rotation. The color-coded block on the right of the screen shows red for harder rock formation and yellow or green for softer formation. This helps him anticipate what changes may be required in the hole. He said the color bar is nice to have, but it’s still just a guide. Riddle said the average shift completes about 18 45-ft holes, but there are some eight- to 12-hole days and he’s seen as many as 50 a day. Atlas Copco’s Western Region manager, Jon Torpy, has been in mines all around the world. About the rock at Newmont, Torpy said, “We, as Atlas Copco, have only seen a handful of locations that have the difficult drilling conditions found at Phoenix,

and the PV-271, coupled with the TD65 hammers, are the best tools for the job.” Maintenance superintendent Walt Holland is responsible for the entire mine’s equipment maintenance at Newmont’s Phoenix Mine. He said that he looks at mining equipment like a three leg stool – drills, shovels, trucks – and all have to be working to keep things moving. Because of the hardness of the rock, “drill maintenance is very important at Phoenix,” said Holland. Other Newmont properties may drill 120 to 130 ft an hour, but at Phoenix, they are now up to 60 ft per hour. “The rock hardness at Phoenix is unique to the world,” he pointed out. “What I like about the Pit Viper rig is its quality. I am getting 92.5 percent availability and that is really good.” The operators were given additional training required for the single pass rig and they feel very comfortable operating them now. “We have a great history with Atlas Copco and have worked right through any issues that have come up,” Holland said. In recent months, productivity at Phoenix has increased and Holland credits this in part to good communication between operations, maintenance, and engineering. “Phoenix is successful because we don’t get conflicting missions. We work well together and challenge each other. The ground is unforgiving at Phoenix and it takes a team approach to be successful. When mechanics and operators are talking, you know you’re winning,” he said with conviction. Mark Evatz echoed this sentiment. “There had to be a steep learning curve at Phoenix,” he said. Since operations began, the most recent quarter was the best at Phoenix from an operation standpoint. “More revenue at a reduced cost has had a lot to do with technology and the application of the Pit Viper rigs,” said Evatz. For Evatz, continuous improvement is a large part of the success at Phoenix. “We had 96 of 100 points right when we started up Phoenix,” he said. A lot of the original planning decisions came from the best practices used at other Newmont Nevada mines, such as the Lone Tree Mine. “We looked at the hardest rock at Lone Tree as a comparison Blasthole Drilling in Open Pit Mining

Unforgiving ground

when beginning operations. Basing equipment estimates and mining practices on Lone Tree’s numbers, our drill production was half of Lone Tree’s,” Evatz said. For another equipment example, Evatz said dozer grousers require replacement three to four times faster at Phoenix than Lone Tree. Although the overall mining rates were comparable at ~150k tons per day, the rock hardness/abrasion at Phoenix is substantially greater. Major consumption items such as down-the-hole hammers and bits are a large ticket item when hammer drilling, but necessary in very hard rock. The mine uses about a dozen TD65 hammers a month and hundreds of 6¾-inch bits. To maximize performance, Atlas Copco has placed a full-time Product Support Sales Representative (PSSR) in the mine to support and develop the use of consumables. His responsibilities include everything from evaluating bit and hammer performance, maintaining hammers, and sharpening bits to flipping a casing in order to maximize hammer life. Jim Wheeler, Atlas Copco senior area manager for consumables in the Intermountain Region, said, “Having someone on-site is all about continuous improvement.” An example of this was a recent insert change on the 6¾-inch hammer bit’s gauge row, which has increased bit performance. Having someone there watching the performance of all consumables ensures that all pieces are working together, reducing drilling costs and improving productivity.

Maximum productivity The TD 65 is a robust, high-powered down-the-hole hammer designed for maximum productivity in combination with large drill rigs. At Phoenix Mine it is equipped with 165 mm (6¾ in) button bits but will also take bits up to 216 mm (8½ in). The TD 65 also ranks as the most powerful hammer on the market, delivering 2,160 blows per minute at the maximum air pressure of 30 bar (435 psi). Jim Wheeler, Atlas Copco’s senior area manager, said it was chosen for its high penetration rate and that it has been living up to expectations since delivery. “The hammer has been Blasthole Drilling in Open Pit Mining

A PV-271 coupled with TD65 hammers have proven to be the best tools for the job.

in daily operation since the Pit Viper arrived at the site and everything is going well. We are getting a penetration rate of 60 to 180 feet (20-50 m) per hour.” About 150 bits are used per month, and in these extraordinarily abrasive conditions, regrinding is not considered an option. However, in order to reduce bit consumption as much as possible, Secoroc has changed the carbide in the buttons to a tougher grade. Wheeler said, “Back in 2007, Newmont Phoenix was testing several hammer and bit manufacturers. They chose us because our equipment drills faster and lasts longer. They also agreed to use only Secoroc consumables on the understanding that we would take the responsibility for the on-site service and maintenance. The mine is very positive to this arrangement and definitely sees the benefit of this kind of service.”

At the site, Tony Silva, who is responsible for stocking the spares and rebuilds the hammer when required, uses the Secoroc rebuild kit to replace the back head, ham mer case and chuck. Other hammers previously used at the site did not stand up as well to the abrasive conditions, particularly the outer parts which are usually the first to wear down. However, on the TD 65, the backhead, hammer case and chuck are all designed using a thicker material. Replacement parts are required. In addition, the TD 65 has a reversible hammer case so when the lower end becomes worn (most of the wear occurs from the bottom up), it can simply be disassembled, flipped over and drilling can continue. Atlas Copco estimates that the hammer can normally be rebuilt two to three times before the outer parts need to be 93

Unforgiving ground

Cutting backheads – cemented tungsten carbide inserts – protect the hammer and case against wear. They also help to prevent the hammer getting stuck in the hole.

Robust and high-powered: These TD 65 hammer components prevent exceptional wear in abrasive rock.

replaced. Other features designed to give increased productivity include a special “hardbody” chuck, a patented Quantum Leap air cycle which powers the piston to more than 80 percent of the stroke, and a patented Air Select regulation system which enables the air consumption of the hammer to be more precisely matched to the air output of the compressor.

The hammer that won the battle of Phoenix rock When the Atlas Copco Pit Viper 271 was put to work at the Phoenix Mine, the down-the-hole hammer was a crucial part of the overall solution. Drilling conditions in the region known as the high desert in northern Nevada are among the most challenging in the world. The 94

quartzite encountered here is notorious for its hardness, and nowhere is it more abrasive than at the Phoenix Mine, located just south of Battle Mountain. “Anything that touches Phoenix rock wears out fast. Here the rock fights back,” stressed Mark Evatz, mine manager. Evatz added that incorporating someone from Atlas Copco onto his team has allowed them to share the successes and failures, and has helped fix issues as they come up – the first time. There is no finger pointing, just solutions for Evatz. Despite the tough geological conditions at Phoenix Mine, Atlas Copco was confident that the Pit Viper 271 and, in particular, Secoroc’s Total Depth TD 65 down-the-hole hammer were up to the task. When Newmont began operations at Phoenix, it was estimated that $205

Helping Pheonix to maximize performance: Jim Wheeler, Atlas Copco’s Senior Area Manager, says: “The TD65 has been in daily operation since the Pit Viper arrived and we are getting a penetration rate of 60-180 feet per hour.”

million would be necessary to build and start up the mine. After two years, those numbers were closer to $230 million due to escalated construction labor and material prices. Although mining took time to reach the desired production levels, it has been achieved. Evatz concluded, “We looked at an aggressive ramp-up with Phoenix. We can accelerate problem solving by working together with Atlas Copco and Cate Equipment, which makes us all more successful.”

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 2 2008. Story and pictures by Scott Ellenbecker, Ellenbecker Communications. Blasthole Drilling in Open Pit Mining

geita, Tanzania

Increasing hole diameter at Geita Gold Mine

The DML drill pattern with 8-inch or 9-inch hole diameters gets blasting engineers the fragmentation they want.

Doing more with less As the pits at the Geita Mine ma- tured, the need to increase tonnage took on a priority. Cut 4 on the main pit was too large to complete in the appropriate time using an Atlas Copco ROC L8 fleet. Mine planners worked with the Atlas Copco Drilling Solutions staff to expand the bore hole diameter and select the drilling fleet to meet these challenges. The result: increasing the hole diameter and pattern spacing led to increased productivity at a reduced cost.

DML high-pressure drilling As Tanzania’s most well known mining operation, Geita Gold Mine, an Anglo Ashanti property, constantly tries to increase productivity as it manages its three-pit operation. At one time, Geita utilized only crawler drill rigs using Atlas Copco’s ROC L8. That evolved to incorporate Blasthole Drilling in Open Pit Mining

Atlas Copco DML low-pressure blasthole rigs in 2006 to improve productivity in non-ore producing formations. Today, the mine continues to use crawlers, but is stepping up its use of the DML – now using high-pressure air and Secoroc COP 64 Gold hammers – to increase productivity in the ore body. Powder factor is calculated by taking the mass of explosives divided by the total volume of rock moved per hole. This volume is from the burden, or the distance from the blasthole to the free face, spacing which is the distance between holes, and hole length. Blasting engineers at Geita use this equation to determine the proper amount and type of explosives necessary to reach the desired fragmentation of the rock. Two different explosive emulsions are used at Geita. P400 is a 20 percent ammonium nitrate to 80 percent emulsion; P700 is a 35 percent ammonium nitrate to 65 percent emulsion. The P400 offers more shockwave energy,

whereas the P700 offers more gas or heave energy. The P400 is used in hard rock and ore for maximum fragmentation because the shock energy reflects back into the formation, increasing breakage. P700 is used when opening the pit as this is primarily mechanical energy. For Geita, the mine’s different explosive techniques mean workers have to consider what they’re doing to maximize productivity of the f leet at all times. Currently the crusher at Geita has a capacity of 15,000 tons per day. The

By increasing hole diameter, spacing and burden, the number of drill rigs could be substantially reduced (photo from May 2005).

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Increasing hole diameter at Geita Gold Mine

Big hole blasting at the Geita gold mine.

goal of the drilling and blasting engineers − led by Gerhard Engelbrecht with calculations coming from engineers Zebedayo Mumusi and Mavindi Edward − is to keep the tonnage up with fewer holes drilled. “Drilling is more expensive than explosives,” pointed out Engelbrecht. With an average of 85,302 feet drilled per week, the month of May produced a total of 331,365 feet for a total of 1.9 million banked cubic meters (BCM) drilled. The ore body density at Geita is 2.7. (BCM is the total volume of rock moved per one blasthole.) Geita operates two shifts, measuring availability on 17 hours per day of drill time with five hours for maintenance. The operators work through lunch, eating at their station. The average BCM per day is 64,000. Interestingly, when the workers were given a break for lunch, the productivity dropped to 58,000 BCM per day. Zebedayo Mumusi equates this drop in productivity to the anticipation of taking a break, resulting in a reduction in efficiency.

Increasing hole diameter Today the mine operates six DML rigs and plans to add two more. This will 96

result in a reduction in their crawler rig numbers. The DML drills 9-inch or 8-inch hole diameters using a Secoroc COP 64 Gold 6-inch hammer. The crawlers, on the other hand, drill a 4-inch hole. Increasing the hole diameter has allowed the mine to increase the pattern spacing resulting in lower costs. Mumusi said, “The increased size equates to a 5-percent reduction in costs for blasting materials alone.” The smaller rigs operate on a pattern of 12 feet for burden and 14 feet for spacing. The large DML operates on a 15-foot x 18foot pattern in the ore body in the Star and Comet pits and 16 foot x 19 foot in the Geita Hill and Nyankanga pits. In overburden and surface work the pattern is increased to 23 feet x 26 feet and 20 feet x 23 feet in transition areas. Currently the bench depth is 36 feet, but Mumusi said the plan is to increase the hole depth to 49 feet. This is not a problem for the DML as it uses a 35-foot drill steel with a 21-foot starter pipe. “The plan is to concentrate on larger hole sizes – bigger holes and fewer holes translates to better performance at a reduced cost,” said Engelbrecht. Mumusi agreed, “My goal is to have fewer holes and continue getting the same fragmentation; the DML lets me

A worker changes the bit on the Secoroc COP 64 Gold DTH hammer.

do that.” Currently the crawler rigs drill an average of 59,055 feet and the DML rigs drill 29,528 to 36,089 feet per week. But Mumusi said, “I get much more BCM with the DML.” Geita will continue using two sizes of drill rigs, utilizing the smaller crawler rigs for situations such as trim shots and inner-face drilling locations where a small rig can maneuver better. However, the DML rigs will be the work horses for production drilling. The DML high-pressure blast hole rigs were originally purchased for overburden and surface work, but are quickly becoming the big production machines and are a major factor in increasing productivity at Geita.

Acknowledgements This article was written by Scott Ellenbecker after a visit to the Geita Gold Mine in July 2009.


Guerrero State, Mexico

Going for gold in Guerrero Large scale mining project Filos and Bermajal – collectively known as the Los Filos Gold Project – are set to become the largest gold mining operations in Southern Mexico. Preparation work to reach the deposits, an estimated 5 million ounces of gold, is already under way.

High pressure drilling with DM45 This region of Mexico has never had a large-scale open pit mining operation before. “We’re setting a precedent here,” says Roberto Díaz Colunga, manager of the Los Filos Project. “In two years this will be the largest gold mining operation in the south of Mexico. The project already provides more than 1,200 direct and indirect jobs, and once we reach our steady production rhythm, we’ll be able to refine over 300,000 ounces of gold per year.” The Los Filos Project is located 8 km from the village of Mezcala, approximately 200 km southwest of Mexico City in Guerrero State. The project is owned by Luismin SA. de CV, a Mexican company fully owned by Goldcorp of Canada. Goldcorp is investing USD 232 million to bring the project into production. A fleet of Atlas Copco equipment is already working at the site, with more units due to arrive. Seven DM45HP blasthole drill rigs and two CM760D crawler drill rigs have been acquired by Luismin. The project’s main contractors, Materiales La Gloria and Desarrollos ROD, also use Atlas Copco equipment on their key pre-production tasks. “Before entering commercial production, Los Filos will have had two years of pre-production development and Bermejal one. This is a key phase for the project and it’s important that Blasthole Drilling in Open Pit Mining

Two of the 15 ECM 350 drill rigs belonging to Desarrollos ROD, which is in charge of constructing the leaching pad at Los Filos.

97

Going for gold in Guerrero

United States of America

Mexico

Gulf of Mexico

Mexico city Los Filos

Pacific Ocean

The Los Filos project is located some 200 km southwest of Mexico City.

we have the right type and quantity of equipment in place,” says José Caracheo Brunel of Los Filos Mine Planning Department.

Two deposits, one project The project comprises two separate gold deposits, Los Filos and Bermejal, which 98

are found in adjacent hills approximately 1,200 m above Mezcala. A feasibility study was originally completed in 2005. This study was recently expanded to include the adjacent, and subsequently acquired, Bermejal deposit. The Los Filos and Bermejal deposits will be developed as a twin open-pit, heap-leach operation, using

two different ore processing methods depending on grade. The mine reserves and resources total over 5 million ounces, of which 4.5 million ounces are in the proven and probable reserve categories. Higher grade ore (1.50 g/t of gold) from the Los Filos deposit will be crushed to 80 percent at –19 mm and agglomerated before being conveyor stacked and heap leached, whereas lower grade ore (0.55 g/t of gold) from the Los Filos and Bermejal deposits will be hauled from the open pit directly to the leach pad to be bulk heap leached. The recovered solution will be treated to obtain a final gold ore product on site. Exploration drilling continues on pit extensions and, in particular, on identifying higher grade areas.

200-million tons of ore The mine development plan calls for a sequence of five mining phases over a 10-year period for both deposits. Under the plan, a total of 200 million tons of ore will be mined with an average gold grade of 0.69 g/ton and an overburden strip ratio of 1.5 to 1. The stripping will entail the removal of 300 million tons of overburden to access the gold bearing ore. The project will process 24 million tons/year of ore. A pre-production of 14 million tons/year is required for each deposit. To develop the ore bodies, conventional open-pit mining methods will be employed using 12–15 cubicmeter capacity loaders and shovels and 91- to 146-ton capacity trucks. The pit design for both deposits incorporates 12-meter high waste benches and 6meter high production benches. Final average slope angle will be 48–52 degrees depending on the type of rock. “We expect almost all the material will require blasting; the reason for blasting the ore on 6-meter benches is to provide better ore control and limit dilution,” explains Caracheo Brunel. The operational cycle will start with the drilling of 175-mm and 114-mm diameter blast holes in the waste and mineral strata respectively. To achieve this, Luismin has ordered a total of seven DM45HP blasthole drill rigs. The DM45 is a high pressure, crawler Blasthole Drilling in Open Pit Mining


mounted, hydraulic tophead drive, multi-pass rotary blasthole drilling rig specifically designed for production blasthole drilling. Operation of the drill is performed using electric-over-hydraulic controllers, ergonomically located so that the operator faces the drill centralizer bushing while drilling. Two of the seven units ordered were delivered in 2005 and are already hard at work on the site, equipped with Secoroc ballistic button bits. A third unit arrived in May with two more units arriving in June and then two more in August. “We only ordered the last five machines once the Bermejal deposit was acquired. Some of these units will work in the Los Filos deposit and some at the Bermejal deposit,” says Caracheo Brunel. “We acquired the DM45 model because it is the ideal size and capacity for the production volume we’ll be managing here.”

Demanding topography The two CM760D crawler drill rigs with DTH hammers were delivered in 2005. “These machines are very useful. They are currently working on bench development but later we plan to use them for pre-splitting,” says Caracheo Brunel. Díaz Colunga, project manager, adds, “We had seen the CM760 working before; they have the versatility needed to access this demanding topography, which doesn’t offer many possibilities of large spaces during the opening of the benches. Because of this, they are ideal for preparation tasks. Also, we required a machine able to conduct detailed work such as presplitting and road construction. These units are good for these jobs.” Díaz Colunga continues, “We have also chosen these machines, both the DM45 and the CM760D, because of Atlas Copco’s proven experience. This reassures us of the equipment’s good performance to guarantee the drilling, which is the first, most important step in the whole production cycle.” About 25 contractors are at work on the project. Materiales La Gloria – the main contractor – is a regular Atlas Copco customer, and its fleet of equipment at Los Filos includes T4BH, Blasthole Drilling in Open Pit Mining

Specifically designed for production blasthole drilling: one of seven DM45HP drill rigs used at Los Filos to keep the project on schedule.

99


Backbreak holes Berm

5m

Production holes

ø 11-12 ¼" ø 6"

15 m

5m 72 º

5m 6m

5m

The drilling and blasting pattern at the Los Filos mine showing the angle of the drill holes.

ECM350 and ECM590 drill rigs. Recently, the company ordered two CM780D crawlers with DTH hammers. Meanwhile, another major contractor, Desarrollos ROD, has a f leet of 15 ECM350 rigs operating at Los Filos. Asked about the performance of the Atlas Copco equipment, Díaz Colunga says, “So far we are satisfied as their performance has matched our plans and expectations.” He notes that the project hasn’t yet reached a normal production rhythm. “We believe we will be more satisfied with the drilling results if we together look after two very important factors – the discipline in the operating habits that we transmit to our personnel, and the meticulous respect for the preventive maintenance program. Other factors are covered by engineering design and Atlas Copco’s experience, in which we have complete faith.”

Specialist support Madisa, the local Atlas Copco distributor, is responsible for technical support at Los Filos and is supported by specialists from Atlas Copco’s Mexicana 100

office. Juan Carlos Gómez, Atlas Copco product manager, explains that upon delivery of a new drill rig, an Atlas Copco specialist will train operators on the use of the rig. “At the same time, Madisa sends its mechanics and instructors so they can participate in training and become even more familiar with the machine.” This training is now even more important for Madisa, which has secured a full maintenance and repair contract at Los Filos. Operators of the recently delivered DM45 and CM760D rigs are trained in a three-week program and technical visits help to reinforce their knowledge. Javier García Adame and Rosalino Carreia Soto are two of the operators of the DM45HP rotary rigs. García, who has been working for the project for over a year, had been operating the DM45 for nearly four months when Mining & Construction visited the site. “It was a comprehensive training process but easy to take on,” he says. “I have no problems with the machine and feel I know it quite well now.” Carreia, who has been working at the project for six months, is still going

through the training process. “There are lots of things to learn but it is not complicated at all. And the specialist giving the training is good too. I’m looking forward to finally operating the machine all by myself!” Díaz Colunga reaffirms the importance of the training. “We have had the benefit of the specialist training that AtlasCopco instructors have given to our operators. “I am convinced that in the future this link will be crucial to strengthening the success of our operations.” The project is at an advanced stage of development. Construction is well underway and is expected to be completed by the end of 2006 with commercial production planned to start in the second quarter of 2007. Commercial production for that year is expected to be 200,000 ounces of gold, rising to 350,000 ounces by 2008.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 2. 2006.


eastern Australia

Coal mining in eastern Australia Hunter Valley Shipping 260 million tonnes in 2008, Australia is the world’s largest exporter of black coal. Roughly one third comes from coalfields in New South Wales, two thirds from those in Queensland. Pit Viper 275 rigs are contributing to production from the Hunter Valley in New South Wales and the Bowen Basin in Queensland.

Multi-seam, multi-pit mining Coal production and export is a very serious business in the Hunter Valley, New South Wales. Normally one train passes through Muswellbrook carrying coals to Newcastle, Australia’s major coal shipping port in 2008, every 20 minutes, said Robert (Rob) Swan. Muswellbrook (pronounced Musselbrook) lies pretty central to the main Hunter Valley coal mines; it is where the Atlas Copco office and service facilities for the area are located and where Rob, who is the Regional Manager – Eastern New South Wales, is based. It is also quite close to the Hunter Valley Operations (HVO) “which has proved very convenient for us”, said Dale Radnidge, the HVO Maintenance Supervisor, whom we met at an office complex known as Cheshunt Bathhouse located in the southern section of the HVO. Located 24 km northwest of Singleton, the Hunter Valley Operations, are 100% owned by Coal & Allied Industries Ltd, which in turn is managed by Rio Tinto Coal Australia. Rio Tinto describes the Operations as a multiseam, multi-pit open cut mining operation. HVO comprizes: part of the Howick mine, now known as the West Pit, which started operating in 1968; the Hunter Valley No. 1 mine, where production began in 1979, and the Lemington mine, which commenced coaling in 1971. Coal & Allied merged the Howick and Hunter Valley mines in 2000 to create Hunter Valley Operations Blasthole Drilling in Open Pit Mining

In the Hunter Valley, New South Wales, Coal and Allied Industries mines a multi-seam, multi-pit operation.

and included Lemington when it was acquired in 2001. The company will approximately produce between 10.5 and 13.5 Mt/y. In addition to the Hunter Valley Operations, the Coal & Allied portfolio includes the quite new Bengalla strip mine 4 km west of Muswellbrook and the integrated Mount Thorley Warkworth open cut mines 15 km southwest of Singleton.

Purchase factors Dale Radnidge explained that there had been various reasons why Coal & Allied (C&A) wanted to buy the Pit Viper 275. For one thing, it would be fitted with the Cummins QSK 19 Tier 2 compliant engine that will meet the relevant Australian environmental impact regulations for some time to come. C&A had good previous experience with the Pit Viper’s predecessor rig, the DM-M2, which was bought in 1995. This has always been a very cost effective machine for the company, with very good life cycle costs – despite the fact that the rig has had to operate for periods in

ambient temperatures of over 50° C. Dale had also had positive feedback from Pit Viper owners concerning the steps taken by Atlas Copco Drilling Solutions to improve features that had been weak points on the older rigs. At the crunch, Atlas Copco quoted a competitive purchase price and the component life cycle costs were acceptable. Atlas Copco also offered to provide a maintenance technician for 12 months: previously an Ingersoll-Rand Drilling Solutions rig owner himself, this technician has also helped the Atlas Copco team at Muswellbrook to identify maintenance issues.

Regulatory issues However, life is not too simple for equipment purchasers in Australia, especially in New South Wales where the government guidelines on equipment specifications, primarily designed for machinery operating in coal mines, are the most stringent in Australia. Rio Tinto Coal Australia management also has very strict rules covering equipment specifications and it was necessary to 101

Coal mining in eastern Australia

workshop. They could therefore make recommendations as to the changes to be made in addition to those modifications necessary for regulatory reasons. These additional alterations were intended to make it easier to maintain the PV-275. Meeting NSW electrical equipment requirements necessitated taking out the whole electrical system and installing a different one. Some of the hydraulic system components also had to be changed.

Operation

HVO Maintenance Supervisor Dale Radnidge (right) with Atlas Copco’s Rob Swan.

have the standard version of the PV-275 modified in a number of respects. Dale Radnidge, the maintenance electrician and maintenance fitters at HVO were involved and so was the unit’s production trainer. The order was placed late in 2007, not too long after the AIMEX mining equipment show in Sydney, and Atlas Copco was able to deliver the PV-275 that had been displayed - in yellow and black livery – to the Muswellbrook workshop. C&A also ordered a new Atlas Copco DML rig that required rather more modification than the Pit Viper. Mr

Radnidge explained that a major aim of purchasing these two rigs was to start to create a unified fleet of different size drills with a common cabin design so that each operator can easily switch from one model to another when necessary. The DML rig has replaced an existing competitor machine, whilst another elderly competitor machine had been put on stand-by when the PV-275 started work.

Modifications The HVO maintenance team were able to inspect the Pit Viper at the Atlas Copco

The Coal and Allied Ltd Pit Viper 275 is fitted with a Cummins QSK 19 Tier 2 compliant engine.

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The mines presently use a walk meter and laser depth indicator in conjunction with mine survey data for drill positioning as the hardware needed to use the GPS system on the PV-275 is not in place yet. The DML has the Aquila system fitted for use with HVO’s Modular Mining Dispatch f leet management system. Dispatch is also being used to monitor the availabilities being achieved by the two new Atlas Copco drilling rigs. At the time of the visit, the Pit Viper was being used with five rods to drill 54 m holes in overburden for blasting and stripping by either dragline or shovel. However, the drilling requirements range from 10 – 60 m depth although the bulk of the benches are drilled with 30 – 40 m vertical holes. Hole size is 7⅞ in for coal and partings and 10⅝ in for overburden. Pre-split holes are drilled at either 10 m or 80 m spacing, in both cases at a 15° angle. Approximately 20 – 25% of drilling time is spent on the pre-splits. All nine drilling rigs working at HVO use Secoroc tools provided through a separate supply and service contract that has been in force for six years. HVO has two Bucyrus International draglines (1 x 1370, 1 x 1570), six P&H electric shovels and a Terex-O&K RH70 hydraulic excavator. As well as the Atlas Copco drilling rigs there are six older ones from other manufacturers. Mr Radnidge explained that this mixed fleet was built up as a result of the merging of the mines that are now part of the Hunter Valley Operations. C&A has been using the maintenance planning tools in the SAP software portfolio since May 2008. Blasthole Drilling in Open Pit Mining


C&A intends to create a fleet of different size drills with a common cab design so that each operator can switch easily from one model to another.

Summarizing, Dale Radnidge said that not only was the deal which Atlas Copco offered sound but the working relationship that C&A has established with the Atlas Copco team has been good too. C&A is comfortable with the purchase. Indeed, HVO had planned to buy two more rigs, which had been shipped to Australia. However, in the current economic climate this will not be possible during 2009.

Queensland – Drillpro Services The vast Bowen Basin coal deposits in mid-Queensland extend from the area west of the coastal city of Bowen to south of the Tropic of Capricorn in an area which lies west of Gladstone. The mines are connected by rail lines to five major ship loading Coal Terminals: Abbott Point near Bowen, Hay Point and Dalrymple Bay near Mackay, and the RG Tanna and Barney Point terminals Blasthole Drilling in Open Pit Mining

near Gladstone. The Bowen Basin accounts for roughly half the world’s seaborne trade in metallurgical (coking) coal. Drillpro Services is a drill services and drilling contracting company formed by John Anderson, who had previously worked in a senior position for a major Australian equipment dealer handling machines competing with the Atlas Copco Drilling Solutions range. Having started out selling drill rig parts and doing rig rebuilds, Drillpro bought its first rig for contract drilling in 2001, followed by two more each year after that. For some time the company used the rigs John Anderson had previously sold, but later Drillpro experienced problems with a particular model so Mr Anderson decided to try the equivalent Pit Viper 275. He is now an enthusiastic customer and advocate.Currently the company has two Pit Vipers working at widely separated mines in the Bowen basin. The first to be delivered

The HVO Pit Viper was being used to drill 54 m holes in overburden, using five rods.

Hole sizes are 7 7/8 in for coal and partings, 10 5/8 in for overburden.

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Drillpro Services deploys one of the company’s two PV-275 rigs at the Wesfarmers Curragh Pty Ltd Curragh North extension.

is at the Curragh operation between Blackwater and Emerald, one of several mines lying close to the Tropic, and the second about 300 km further north at the Coppabella mine.

Phil Smith finds the Curragh Pit Viper easy to use.

104

Curragh North Operated by Wesfarmers Curragh Pty Ltd, which is wholly owned by Wesfarmers Ltd, the Curragh mine was first

developed by an ARCO-led consortium mainly to supply thermal grade coal to the Stanwell power station near Rockhampton in Queensland. Subsequently metallurgical coal production has grown and the company exports this grade together with surplus thermal coal. Target export tonnage for the Financial Year July 2008 – June 2009 was 7.0 Mt while 4.0 Mt would go to Stanwell. Production from the original Curragh mine has been supplemented by the development of the Curragh North extension. There are three draglines working at Curragh and two at the extension, where there are also hydraulic excavators loading Caterpillar trucks (793 and 789 models). Both types of coal are mined from this extension: one grade is taken to the coal preparation plant at the original mine by a belt conveyor, the other is hauled by large high-sided truck-trailer units. The plant also washes coal from Yarrabee, some 25 km to the north. Thiess has the overburden stripping contract at Curragh North, with Drillpro doing the drilling and other specialist firms, including Orica, carrying out the blasting. The overburden is mainly sand and gravel. John Anderson explained that Drillpro Services has worked at Curragh for 11 years. Under the current threeyear contract the company operates and maintains two drills that belong to the mining company as well as the one PV-275 and one DM-M3 that Drillpro owns itself. The Pit Viper is working at the Curragh North extension. From January 5 to January 18, 2009 Drillpro had drilled 51,000 meters, as compared to the mine’s target of 25,000 m/week. This requires a penetration rate of 850 m per 10 hours drilling per shift. However, Curragh was looking to increase the rate to 30,000 m/week. From early August 2008, when the PV-275 started work, up until the time of our visit on January 20, 2009, the rig had drilled 130,000 meters. The rig was still using the original drill rods and had thus far achieved 98% availability, Mr Anderson said. Both this Pit Viper and the one at Coppabella drill 270 mm holes. However, the Curragh machine has a Cummins QSK engine while the Coppabella PV-275 has the Cat C27 option. Blasthole Drilling in Open Pit Mining


Usually Drillpro uses a DM-M3 for drilling 25° pre-split holes and 20° bench holes for cast blasting. Sometimes, commented John, Drillpro gets held up because the pre-split holes are not blasted soon enough. However, the area we visited had a soft wall so pre-split drilling was unnecessary. We watched Phil Smith operating the PV-275. He drilled the A/O hole to 51m and the holes H11 to A11 to between 47 and 50 m. Phil Smith has 17 years’ experience in exploration drilling followed by 3½ years of production blasthole work, including drilling with the DM45 and the Driltech D75 rigs. He told us that the PV-275 is better than both of them: it is easier to use and has more feel for the drilled rock. The cabin’s perforated blinds were very helpful in the bright Australian sun, eliminating glare but providing sufficient visibility for Phil to move the rig from one hole to the next drilling position. John Anderson remarked that he would like to have a window in the cabin roof to provide a view of the mast, but the design of the FOPS cab makes this impossible. Instead there is a camera system which the operators took some time to get used to, but now find perfectly satisfactory.

Modifications As in New South Wales, though to a slightly lesser extent, some modifications are essential to meet the Queensland government guidelines, explained Don Emery, who is Atlas Copco’s Regional Manager, Mackay. And although John Anderson could not have his roof window, he did get several substantial modifications that he asked for. The Curragh Pit Viper was shipped into Brisbane, trucked to the Mackay workshops where it was modified, trammed into the Queensland Mining Exhibition held from July 24-27, 2008 and then delivered straight to the mine site. In carrying out the alterations Atlas Copco was considerably assisted by an adjacent firm of boilermakers which could generate the required drawings and do some of the fabrication. In addition to rewiring according to Queensland standards, the main Blasthole Drilling in Open Pit Mining

The second Drillpro PV-275 works at the Coppabella & Moorvale JV’s Coppabella mine.

modifications and additions included: a modified walk-up ladder; one platform in front of the cabin and another to provide high level access to the

mast; a Hiab crane, with its own power supply mounted under the cabin, to help with drill tools handling; addition of a Chubb fire suppression system on 105


a rail around the engine; two lifting hooks; and a microwave and fridge. Several of the standard features were relocated for greater convenience, such as the isolators, which were moved to the back end of the frame to be within reach from ground level, the Wiggins fast fill unit and the lube drums. Phil Smith was particularly enthusiastic about the Hiab crane which makes his life a good deal easier, he said. The Coppabella machine was delivered with the lift hooks pre-fitted, an upgraded engine fire suppression system and greasing access for the driveline to the pump. In addition, extra tanks were fitted for dust suppression so that refilling is required after two shifts. As well as a Hiab crane and extra platforms like those on the Curragh Pit Viper, there is an access to the mast and the camera on the mast via the top of the cabin.

Coppabella The overall operation and the mining operation at Coppabella are managed by Macarthur Coal (C & M Management) Pty Ltd – working on behalf of the Coppabella and Moorvale Joint Venture. The Joint Venture comprizes Macarthur Coal Ltd (73.3 % stake held via Coppabella Coal Pty Ltd); CITIC (via CITIC Australia Coppabella Pty Ltd), Marubeni Corp. (via Mapella Pty Ltd), and Sojitz Corp. (via Winview Pty Ltd) each holding a 7 % interest; JFE Shoji Trade Corp. (3.7 % held via KC Resources Pty Ltd); and Nippon Steel Trading Co. Ltd – 2.0 % held via NS Coal Pty Ltd. The coal handling and preparation plant has a capacity in excess of 6 Mt/y raw coal and is operated by the Sedgman Coppabella Joint Venture. The mining lease was granted on June 1, 1998, overburden removal started in July 1998 and the first coal was mined in October 1998. By April 2007 Coppabella had yielded 40 Mt of run of mine coal. Macarthur Coal’s attributable production in 2008 was 2.57Mt. Proven and probable reserves totalled 67 Mt as at 30 June 2008. The operation is located adjacent to the Peak Downs Highway, 140 km southwest of Mackay between Nebo and Moranbah. It mainly produces a 9% ash, 106

Drillpro’s Pit Viper 275 rig at the Coppabella mine, seen here in the Johnson Pit South, is equipped with the Caterpillar C27 engine option. The machine drills 20° angled pre-split holes and either 20° or more often vertical main bench holes.

low volatile PCI grade metallurgical coal that is railed to the Dalrymple Bay Coal Terminal near Mackay. But, in response to market trends, Coppabella has revised its mine plan in order to mine thermal coal and reduce PCI grade output, demand for which has fallen sharply. This also meant that 140 people were laid off in mid-December 2008. John Anderson’s son Matt joined Drillpro Services in 2003 and now manages four contract sites in the area. Of these Coppabella, where Neal Torresan is the company’s site supervisor, is the largest but the other clients are prestigious – BHP Billiton Mitsubishi Alliance (BMA), whose Poitrel mine is operated by the contractor Leighton; Vale Australia’s Broadlea; and Peabody’s Eaglefield, where the main contractor is Macmahon. Drillpro was also bidding for work at BMA’s South Walker Creek mine, where Thiess is the mining contractor. At Coppabella, overburden removal is primarily by dragline, coal mining by large excavators loading trucks. Orica is responsible for blasting the holes Drillpro drills under the terms of an 18

month contract. There are presently three producing pits; East, Southern and Johnson. Drillpro has the PV-275 and one other rig operating, one spare machine and one parked unit, all of these being of other make. (When bidding for new contracts having idle machines can help, commented Matt Anderson.) The Coppabella PV-275 rig drills 20° angle, 18 meter pre-splits and 12-18 meter main bench holes, of which some are angled at 20° but most are vertical. The coal is 13-14 m thick in places at a depth of approximately 37 meters below surface. Jason Camielleri was operating the drill during our visit to the Johnson Pit South. Routine servicing of the Coppabella machine’s Cat C27 engine is done by Drillpro but any guarantee work is done by the Caterpillar dealer. At the time of our visit the machine had done about 1000 hours.

Acknowledgements Kyran Casteel, a Contributing Editor for Coal Age and Engineering & Mining Journal, visited the New South Wales and Queensland coalfields in January 2009. Blasthole Drilling in Open Pit Mining

Russia, Southern Siberia, Kuznetsk Basin

Boosting Siberian energy Standfirst Economic growth in southern Si- beria is increasing year-on-year and at the Kuznetsk Basin coal field, new mining enterprises are appearing and existing operations are introducing the latest equipment to boost their productivity.

The DML expectance The Kuznetsk Basin (Kuzbass) is well known for its huge coal resources, half of which, some 693 million tons, are coking coals, the main commercial fuel for smelting iron. Today, more than 100 underground coal mines and open pits are in production with, 17 coal cleaning plants producing different grades. Annual production of power station and coking coals is some 1.5 billion tons. Drill-and-blast contractor AzotCher nigovets Ltd. offers blasted material preparation for the open pit Chernigovsky mine with an annual production of some 6 Mt. “In our f leet there are only foreign rotary blasthole drill rigs,” says Vladimir Bornev, site supervisor. “We drill blocks with five rigs, three of which are Atlas Copco DML rotary blasthole rigs.” The plan for 2007 was to achieve 1.1 million drillmeters and by the 11th month, the company was well on track to meeting this goal. Comparing the DML rigs, the most popular in Kuzbass, with their domestically manufactured counterparts, Bornev says that the Atlas Copco rigs are very productive and maneuverable, with the powerful diesel engine and compressor productivity among the main benefits. “Local rigs achieve a maximum of 10,000–11,000 drillmeters per month, while the plan for our DML is 20,000–22,000 drillmeters per month,” he says. “In fact, one of our drill rigs has broken all records at the mine; in August it drilled 30,500 meters. The DML rigs are built much better, quality-wise, and the design is more sound and reliable.” Blasthole Drilling in Open Pit Mining

The successful Azot-Chernigovets team at the Chernigovsky open pit: (From left) Vladimir Klimov, operator, Oleg Grebenshikov, operator assistant; Dmitry Kuznetsov, foreman; Vadim Khlebunov, deputy chief engineer; Vladimir Bornev, drill site supervisor; Victor Yarkov, operator and team leader; with Yury Dolgov of Atlas Copco.

Victor Yarkov, operator of the recordbreaking DML, says, “The cabin is well insulated, with good visibility and operating lights. Also, the control levers are comfortably located.” Yarkov has worked here for almost 20 years and says good teamwork also contributes to the successful drilling. At Chernigovsky, tricone drill bits are used for the 203 mm and 270 mm blastholes with 9-meter pipes to depths of 5-15 meter. The performance of the rotary head is 100 rpm at 10.575 Nm and the compressor capacity is 34 m3/min at 758 kPa. “Water in the coal beds is about 50 percent, and in some sectors even more,” says Vadim Khlebunov, deputy chief engineer of Azot-Chernigovets. “This, combined with fissuring, often makes drilling and blasting a problem. However, the rig performance is excellent and if you follow the manufacturer’s recommendations, there will be no problems at all.” The contractor produces and uses two types of emulsion explosives for dry and wet holes. “We provide a complete technology process,” comments Khlebunov. “We sell fully prepared cubes of rock mass and run operations

both at Chernigovsky and at a number of other open pits.” The set task per shift for the DML is 400-500 drillmeters, so it achieves 800–900 drillmeters per day over two shifts. Says Khlebunov, “We hold a record of 1,300 drillmeters per day. Our success is the result of coordinated efforts by all those involved. We want to prove what the drill rig and the enterprise is capable of.”

Bachatsky open pit At the Bachatsky open pit, owned by Kuzbassrazrezugol, the average thickness of the coal seams is 32 meters. Here, too, the main goal is to increase productivity at minimal cost. The rig fleet has been completely renewed; the previous 14 electric drill rigs have been replaced with four diesel and two electric rigs. Two DM-M2 and two Pit Viper 271 rigs are in use and the miners are happy with the equipment. Alexander Bogatiriov, deputy technical director, says, “Though the rigs belong to different classes, I think they are equal in terms of productivity. Operators hold the same opinion; the DM-M2 is not second to the Pit Viper. Competition between the rig operators 107

Boosting siberian energy

produces such great results with the DM-M2 as 30,600 drillmeters per month and with the PV-271 37,000 drillmeters per month, which can be compared with a performance of some 8,000 drillmeters per month for the conventional Russian drill rigs.

Single-pass capability The first drill rig was commissioned in 2004 and was the second such drill rig in Kuzbass. To increase productivity, the management decided it wanted single-pass drill rigs and the Pit Viper proved to be the ideal choice. “We have practically reached the maximum theoretical productivity capabilities of the rigs,” says Bogatiriov. “As for maintenance, we observe Atlas Copco factory recommendations. Earlier, the lifetime of the locally manufactured machines was five to seven years, but with the new machines, we expect 10 to 12 years.” Atlas Copco’s local distributor, Mining Solutions, is responsible for staff training and maintenance of the rigs. Engineer Vladislav Grebnev, deputy general director, says, “We have had people on this site from the start, working hand-in-hand with the customer to steadily boost the productivity of the equipment. “The operators traditionally believe that productivity increases depend solely on torque. Pulldown force was not taken into account. We worked together as a team and the rigs started achieving 18,500 meters per month. That was the start of the productivity increase.” The company provides three types of service contracts: a complete service, including night duty; setting up, diagnostics, parameter monitoring; and emergency call-out. Today, 40 units of Atlas Copco equipment are covered by the service contracts and practically all customers extending their contracts choose the full-service option. Service contracts are applicable to all rotary drill rigs including DML, DM45, DM-M2 and Pit Viper 271s in the region.

Acknowledgements A winter’s day at the Bachatsky open pit: The Atlas Copco drill rigs DM-M2 and Pit Viper 271 help to produce coal for both the domestic and international markets.

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This article first appeared in Atlas Copco Mining & Construction No. 1 2008 Blasthole Drilling in Open Pit Mining

USA, Wyoming

Hidden treasure beneath America's western prairie Multi-pass drills meet demand Much of the world relies on coal for electricity generation. This is especially true in the United States, where coal is responsible for over 50 percent of the power produced. To meet this need, over 1 billion tons of coal is mined on an annual basis. The proven DM-M3 and now the PV-275 are the drills of choice in large scale mining operations in Wyoming. These robust drills, with their ability to drill large deep holes at an angle, have become the standard in the Powder River Basin.

Powder River Basin Under the rolling grasslands of northeast Wyoming, massive seams of lowsulfur, sub-bituminous coal are mined on a scale unmatched anywhere on earth. The Powder River Basin (PRB) is home to 13 major open-pit coal mines, all of which would be considered large in their own right. Combined, these mines tallied 451 million short tons (410 million metric tons) of coal production in 2008. Individually, the PRB is home to the 10 largest coal mines in the United States, and quite possibly the five largest in the world. Two mines, Peabody Energy’s North Antelope/Rochelle Mine and Arch Coal’s Black Thunder Mine, each produced over 88 million short tons (80 million metric tons) in 2008. The key to the success of these mines is the thick coal seams, which can exceed 80 feet (24 meters) high. While the geology may seem very favorable, strip ratios continue to increase as mining progresses. Many of the mines now average 3 cubic yards of waste to 1 ton of coal. This translates to overburden cover in excess of 300 feet (91 meters) in many areas. Therefore, to meet the Blasthole Drilling in Open Pit Mining

Massive amounts of overburden - up to 300 ft (91 m) - are removed to reach the seams of coal that can exceed 80 ft (24 m) thick. Powder River Basin coal is treasured because of its low sulfur content.

high coal production, an enormous amount of overburden must be moved.

Dragline operations When moving this amount of material, mines turn to the lowest cost equipment available. Many of the PRB mines utilize large walking draglines as their

primary stripping tool. Draglines are very cost-efficient earthmovers as they utilize massive buckets (up to 160 cubic yards, or 122 cubic meters), and deposit their material directly without need for haulage units or conveyors. Unlike a shovel or loader, which has a limited digging height that dictates the bench height (usually less than 60 feet, or 109

Hidden treasure beneath America's western prairie

Draglines are effective earthmovers, removing overburden and depositing directly into spoil piles as shown here. In the foreground, casted material can be seen filling the empty pit, while dozers work to build a dragline bench.

A dragline digs on the spoil side of the pit. Draglines move in small steps via a cam-type walking mechanism.

110

18.3 meters), a dragline is capable of deep digging depths beyond 100 feet (30.5 meters). While the dragline is a very effective earthmover, the overall cost of overburden removal can be reduced through cast blasting. Cast blasting is a method of drilling and blasting that uses high explosive energy to throw a sizeable portion of the bank into the adjacent empty pit where the coal was previously removed. This method often results in casting 30 percent or more of the bank overburden material to its final resting place, known as the “effective cast” or “cast to final.” As dragline operations require a flat bench, large track dozers with special wide blades (sometimes referred to as carrydozers) push the cast material down and build a bench at a set height above the coal seam. The dragline will then uncover the coal seam. This mining Blasthole Drilling in Open Pit Mining


method allows for the excavating of a large vertical block of material ranging from 100 feet (30.5 meters) to 200 feet (61.0 meters) or more in depth, compared to the 50-foot to 60-foot (15.2 to 18.3 meter) vertical benches taken by truck/ shovel methods. A challenge of the dragline method is maintaining stability of the face (known as the highwall) after excavation, especially when water is present in the material. Drilling for cast blasting applications generally involves deep depths (up to 235 feet or 71.6 meters), large diameters (up to 12 1/4 inches, or 311 mm) and angles up to 30 degrees from vertical. Large diameters result in wider drill patterns, reducing the number of holes drilled. Because of the size of the dragline buckets, large fragmentation size from the blast is not a concern. However, some operations have found that smaller diameters such as 11 1/4 inches (286 mm) yield better blasting results with the tighter spacing. Deep blasthole drilling has its challenges. Foremost is the amount of cuttings generated by the large diameter, deep holes. A 12 1/4-inch (311 mm) hole to 200 feet (61.0 meters), assuming a swell factor of 30 percent, would yield 7.9 cubic yards (6.0 cubic meters) of cuttings. This is a very large pile that smaller drills simply cannot contain under their dust hoods. Even though a small unit might have sufficient pulldown, rotary torque and air to drill a hole, it wouldn't be effective due to excess cuttings falling back down the hole after the hood area is filled. Most of the drilling for dragline operations is done at angles between 20 and 30 degrees. The angle drilling serves two purposes. First, the angle can be set to roughly the same angle as the desired highwall. This is done to help keep a consistent face-row burden to improve the effectiveness of the cast shot. In simple terms, the burden at the top of the highwall (the crest) should be similar to the burden at the bottom of the highwall (the toe). Second, angle drilling can help shape the direction of the cast shot. As the blast projects perpendicularly from the bore hole, an angled hole gives a vertical component to the blast, helping lift the material and therefore throw it further. It is Blasthole Drilling in Open Pit Mining

Drilling at an angle then blasting the bank into the adjacent empty pit results in casting 30 percent or more of the bank overburden material.

important to remember that the drilling depth increases as the angle increases. For example, if mining a 200-foot (61.0 meter) bench, the drilling depth at 30 degrees would be 231 feet (70.4 meters). Some mining regions are fortunate to have soft material, which yields extremely fast drilling rates and less wear on buckets, tires and truck beds. The PRB is in this class, with much of the material having a compressive strength of less than 5,000 psi (34 MPa). The

material is so soft that tricone bits are rarely used. Instead, aggressive clawtype bits are the standard. Contrary to the general belief that soft material calls for as high a rotation speed as possible, these claw bits rotate at lower RPM (100 or less), but their design allows them to shear through the material at rates exceeding 1,000 feet/hour (305 meters/ hour). To handle the high penetration rates, large air compressors must be used. This is especially true in the PRB as these

Drillers on the DM-M3 appreciate the clear view of the breakout wrench and easy access to controls.

111


The 235-ft drill depth of the DM-M3 allows the dragline access to the deep coal in one blast. The DM-M3 can drill at an angle of 30 degrees, which maintains the angle of the highwall and helps shape the direction for the cast shot.

Good highwalls are a result of proper drilling and blasting and bench preparation. The dragline seen here is using the spoil side stripping method as this pit nears completion.

drills often use smaller diameter drill rods to increase the annular area (the gap between the wall of the hole and the drill rod) to allow the larger cuttings generated by the claw bit to exit the hole without having to be reground to a smaller size. High volume compressors of up to 2,600 cubic feet per minute are used, and it is important to have sufficient air pressure (100 psi, or 6.8 bar, or more) available to prevent plugging bits. Because of the light weight of the overburden (approximately 3,000 pounds per cubic yard, or 1.04 tons per cubic meter), bailing velocities may dip below the 5,000 feet per minute (1,524 meters per minute) recommendation that the industry would normally prescribe, yet still effectively clean the hole. 112

Building Drills for the PRB Atlas Copco’s DM-M3 and Pit Viper 275 (PV-275) are ideal for coal mining in the Powder River Basin and the DM-M3 was, in fact, first designed for mining the overburden in the PRB. Jon Torpy, a regional manager for Atlas Copco, said, “The DM-M3 is in a class of its own with the right balance of air, rotary head performance, bit load, and depth capacity. The PV-275 has taken these strengths and added to them. The DM-M3 was designed to drill the Powder River overburden so it can drill the deep angle holes required to reach the coal.” Walt Schroeder is a product support sales representative for Atlas Copco, but prior to working for Atlas Copco,

Schroeder was a driller. He has operated many drills including seven years on a DM-M3. Schroeder said, “I have never had a bad word to say about the DM-M3 and it’s always the truth. Ask anyone who has operated one. There is no other drill that can mast over to 30 degrees and drill 240 feet – all day, every day and never even grunt!” Schroeder added, “When this rig was designed there were definitely miners involved. There isn’t a more comfortable rig to operate; they got it right when they engineered this rig. I’d say this is the most ergonomic drill on the planet and I’ve never run a rig that I like more.” Schroeder’s confidence speaks to durability, too. Availability is critical according to Schroeder. “There is not a drill made that has the air, power and overall drilling performance at this depth and angle that can match the availability of the DM-M3. I know guys you wouldn’t let operate your lawnmower who are drilling with the DM-M3 – this rig is tough!”

Acknowledgements Story and pictures by Brian Fox and Scott Ellenbecker. Portions of this article first appeared in Mining & Construction USA, No. 1, 2009.


USA, Vansant, VA

Moving mountains

Virginia Drilling now has over 50 Atlas Copco drill rigs in its fleet.

A focus on the coal industry In the southern Appalachian range of West Virginia, Kentucky, and Virginia, known as the Blue Ridge Mountains, the seam of coal flows through the ground at varying depths, sometimes just at the base of the mountain. To get the coal Virginia Drilling Company works with their coal company partners to shave off the mountains one 30-ft to 40-ft lift at a time. Virginia Drilling’s business philosophy has developed over time but has remained simple, says said founding partner and company president Verlo Stiltner. “We grow the business by focusing on what you do best and surround yourself with experts.”


Virginia drilling In 1998, partners Verlo Stiltner, David Hale and Mike Sheets started the contract drilling company Virginia Drilling to diversify the existing blasting business, Austin Sales, owned by Hale and Stiltner. The company began as a contract driller on construction applications with Ingersoll-Rand ECM 490 and ECM 690 crawler rigs. Today the company has grown to include 28 Atlas Copco DM45’s, nine Atlas Copco DML’s and seven Atlas Copco crawler drills in various sizes, including one ECM 490 and one ECM 470 and two ECM 690’s and three ECM 720’s. Virginia Drilling is the largest, if not the only, contract driller in the world focused primarily on the coal industry. Even the smaller construction crawler

drills are dedicated to road, reclamation and underground mine face-ups to a point that 85 percent to 90 percent of the work is for the coal mining companies. Two years ago, the company’s cofounder David Hale passed away, but the business has continued to grow with strong leadership and committed employees. Today the company has 18 drills on order and has a steady business growth plan slated for years to come.

Getting started Because of the existing blasting business, Virginia Drilling knew everyone in the area. Founding partner and construction drilling manager Mike Sheets summed it up, “the coal industry in the region is a real fraternity.” Just over a year after starting the business, which 113

Moving Mountains

until that time had focused on construction projects, Virginia Drilling partners were approached by a coal company who knew their blasting expertise and asked them to drill in the coal field. The premise was to not waste blasting material on the bench, to work efficiently and maximize outside resources. The goal was to get costs below industry average and have higher drill utilization.

Partner responsibilities

Two Atlas Copco DML drill rigs prepare for the next shot that will lower the bench to the coal seam.

114

From the beginning Virginia Drilling’s partners accepted that they were not drill experts. Admittedly, Virginia Drilling Chief Operating Officer Clinton Evans pointed out they had lots to learn and wanted to work closely with drill dealer Brandeis Equipment to develop a maintenance program. “When choosing a drill it was really a no-brainer,” said Evans. They went with Atlas Copco because if its product reputation, but also they needed a strong dealer that would support every aspect of the drill including parts and support. According to Brandeis branch manager, Barry Justice, 40 percent of their parts inventory is for Atlas Copco Drills. “If the drills don’t run, the whole mining process stops,” said Justice. Brandeis has 19 service trucks in the field, running its parts department on a double shift and supplying 24/7 service to Virginia Drilling. All that attention equates to a higher performance on the drills. The oldest drill in the fleet is a 1999 DML with 22,000 hours. Typically on a mine site the cost of drilling equipment is approximately 5 percent to 10 percent of the total expenditures. This is another reason why some mining companies don’t focus on their drilling. Virginia Drilling knows that the excavation equipment can catch up to them but can’t pass them. Atlas Copco regional sales manager Tom Borer said, “Virginia Drilling has drills with 20,000 hours on them that run better than drills owned by others that have 10,000 hours.” There is no big secret here; it’s all in the preventative maintenance (PM) program. The main pumps, for example, average 7,000 to 8,000 hours for most, Blasthole Drilling in Open Pit Mining

Moving Mountains

Shouldering the burden for the coal companies. From left: Mike Sheets, Clinton Evans and Verlo Stiltner of Virginia Drilling.

while Virginia Drilling averages 11,000 to 12,000 hours. It’s not uncommon for Virginia Drilling to get 40 percent greater life out of their drill components because of the PM program. Mike Sheets said, “It’s all about taking away problems.” Brandeis takes the burden of maintenance away from Virginia Drilling and Virginia Drilling takes away the burden of drilling and blasting from the coal companies. He emphasized that his customers’ focus is to move material. They don’t want to worry about getting the shot right or all the liability that comes with explosives. Sheets said, “If everyone focuses on the part of the business that makes them money everyone wins, and if we’re not drilling holes, we’re not making money.” To ensure they are drilling holes they follow the PM program religiously. If a drill is close to a scheduled PM and a Brandeis truck is in the area, they will perform the service rather than let it get behind. As a contract driller for many mining operations in the area, Virginia Blasthole Drilling in Open Pit Mining

Drilling takes total responsibility for the drilling and blasting operation. The agreement with its customers is a winwin for everyone. When this part of the business began and the deal was laid out for the customer, he didn’t believe it. “He told us it seemed too good to be true,” said Sheets. They proposed a sliding scale based on 50,000 to 1 million yards of shot material with discounts built in for volume. Virginia Drilling guaranteed the product amount in the customer’s timeframe. They absorb most costs related to putting the product on the ground, from equipment to human resources to blasting material. “When we finished making our proposal the first response was ‘where do I sign,’” said Sheets. Today Virginia Drilling´s client list is long and growing.

Training equals success People are a critical part of making this work. At any one time Virginia Drilling has seven to eight drill trainees, with

that number going as high as ten. The training program has developed over time to what it is today, a well executed system. For the first two weeks they mostly watch and listen. They learn how to set up on the bench, put the mast up and down and terminology. They learn by watching and listening. “We prefer they don’t even come in with experience,” said Evans. They don’t want new employees to have bad habits and to learn drilling according to the company’s operation. After they have a couple weeks with the best drillers they come in for classroom work. They learn down pressure, rotation, penetration rates, bit performance and compressor and engine operation, everything they need to know about the drill and what its responsibility is for drilling the hole. Then the trainees go back in the field with the experienced driller again to apply the classroom work. Every month drillers are evaluated to make sure they are getting optimum production, maxi-mum penetration and bit life 115

Moving Mountains

Blasting off the top – benching down to the coal that can be seen at the base of the mountain.

and overall efficiency. But, all the aspects of training come right back to keeping the drill working at its maximum performance rate. “We expect to get 30,000 hours from our drills,” said Evans. The drillers have to be doing their job correctly to ensure that level of equipment life. 116

Performance for results Drill performance also factors into how Virginia Drilling bids a job. “Everything is evaluated when looking at the cost per foot,” said Sheets. “Because we look at all aspects of the drilling and blasting process, we know how to find our efficiencies.”

One drill site may run into five different layers of sandstone in a mine. Laminated charts plot out the geology of the mine. The goal is to get the maximum penetration in relation to the time in the hole. “The bit is an integral part of the operation,” said Evans. Bits give you the data as to how the drill is performing. Weight and rotation is applied to the bit according to the situation. In this area a driller may expect to get a penetration rate of 6 feet a minute at 165 rpm and 15,000 lbs. Although bits have an optimum rotation rate its only half the equation. “We are not willing to sacrifice a drill to drill faster,” said Clinton Evans. Virginia Drilling looks to maximizing the relationship of down pressure to rotation rpm to ensure the life of the drill. Using 7 ⅞-inch to 9-inch bits on its DML’s and 6 ¾-inch to 7 ⅞-inch bits on its DM45’s, operating between 2,500 to 4,000 hours a year, Virginia Drilling projects 2 ½ million yards of rock a month. It is expected that each drill is responsible for 500,000 yards. The DML’s are equipped with 6 ¼-inch x 30-ft pipe, while the DM45’s run 5 ½-inch x 30-ft pipe. Virginia Drilling can move drills if needed, and to meet the required tonnage they will run three to four drills per site at one time with a maximum of five. Evans prefers the DML because it is beefier from the frame up, but the performance and hole sizes dictate what drills will be used. It goes back to blasting – try to make the pattern smaller but get the most value from the caps, primers and explosives. Generally, hole spacing is on an 18-ft x 18-ft pattern. The 7 ⅞-inch hole can support 16-ft to 18-ft spacing, while the 9-inch hole can do a 19-ft to 21-ft spacing. Virginia uses a 70/30 ANFO emulsion blend as an explosive.

Acknowledgements This article first appeared in Atlas Copco Mining & Construction magazine No 2 2008. Story and pictures by Scott Ellenbecker, Ellenbecker Communications.


DRILLING METHOD GUIDE

Drilling method guide Different applications need different kinds of drilling equipment and performance. The drilling method has normally been established for some time, and well proven techniques are seldom replaced by new methods. This guide is an attempt to start a discussion around the method and equipment that might provide the ultimate solution for an application. Below, we compare three different drilling methods on offer from Atlas Copco.

Rotary drilling methods

The prime difference from other drilling methods is the absence of percussion. Rotary cutting, using fixed type claw or drag bits, is mainly used for soft rock which is cut by shearing. Rotary crushing uses tricone bits relying on crushing and spalling the rock. This is accomplished by transferring downforce, known as pulldown, to the bit while rotating in order to drive the teeth (commonly tungsten carbide type) into the hole bottom as the three cones rotate around their respective axis. The softer the rock the higher the rotation speed. The drill rigs need to be heavy to provide sufficient weight on bit. Generally, drilling below 152 mm (6 inches) is best accomplished by percussive drilling unless prevailing rock conditions are suited for rotary cutting. Rotary crushing is the prime choice for large diameter holes, above 254 mm (10 inches) in open pit mining, overburden stripping at coal mines, and deep well drilling.

The down-the-hole method

The down-the-hole method is a reliable way to drill both difficult and easy rock. The rock drill piston strikes the drill bit directly, while the hammer casing gives straight and stable guidance of the drill bit. This results in minimal deviation and greater hole wall stability, even in fissured or otherwise demanding rock. Since the annulus between the drill pipes and the hole wall is comparatively small, a high flushing velocity is maintained, which contributes further to hole quality. Good hole quality enables the burden and spacing to be increased, which saves time and money. Straight holes make charging easier and enable the amount of explosive to be reduced. The reliable DTH method is an easy way to produce deep, straight holes. From an environmental point of view, the noise emissions and vibration from DTH drilling are comparatively low. This is of particular advantage when drilling in densely populated areas.

The tophammer method

In percussive tophammer drilling the impact energy is generated when the piston is striking the shank adapter. This energy is transmitted from the rock drill via the shank adapter, drill steel and drill bit to the rock, where it is used for crushing. The entire system of rock drill, drill steel, drill bit, rotation, feed force and flushing must harmonize for maximum drilling economy. The tophammer method is primarily used for drilling in hard rock for hole diameters up to 5 inch ( 127 mm ), and the main advantage is the high penetration rate in good solid rock conditions. Handheld pneumatic rock drills are used for small hole diameters while rig mounted hydraulic rock drills are commonly used for hole diameters above 1 5/8 inch (41 mm). Heavy hydraulic rock drills with an impact power of up to 40kW are used for large hole diameters up to 5 inch. To maintain good drill steel economy and hole straightness heavy extension rods or rigid guide tubes with large outer diamer have to be used.

TONS

Principle: Rotation is provided by a hydraulic or electric motor driven gearbox, called a rotary head that moves up and down the tower via a feed system, generating the pulldown required to give sufficient weight on the bit. Flushing of drill cuttings between the wall of the hole and the drill rods is normally made with compressed air.


Principle: The hammer is situated down the hole in direct contact with the drill bit. The hammer piston strikes the drill bit resulting in an efficient transmission of the impact energy and insignificant power losses with the hole depth. The method is widely used for drilling long holes, not only for blasting, but also for water wells, shallow gas and oil wells, and for geo-thermal wells. In mining it is also developed for sampling using the reverse circulation technique (RC drilling).

Principle: In the simplest of terms, the tophammer drilling method goes back to manually hitting the end of a drill steel with a sledge hammer. As recoil makes the rod jump back it is rotated to ensure that the hole is round. In a similar way the impact energy of the rock drill piston is transmitted to the drill bit in the form of shock waves. Drill cuttings are removed from the hole bottom by air or water flushing.

117

specification GUIDE

Specifications guide From a pure technical point some readers may find the definitions and units used on the following pages confusing. Several of the terms and units have a history dating back to the early days when drilling was based more on practical experience than on advanced engineering.

Feed Force For many users and equipment manufacturers feed force is commonly referred to as “Weight on bit”(WOB), and expressed in lb (pounds) or kg. Since this term WOB is commonly used by many drillers, we decided to include it in the specifications pages. The “Weight on bit” is defined as the downward force on the drill bit, generated by the force from the pulldown cylinders combined with the force generated by the weight of the drill string. From a pure technical point mass and weight are different properties and a force can not be measured in pounds since that is a unit for measurement of mass. Since the 18th century pound-force (lbf) has been used for low precision measurement of a force. A more precise definition is the newton (N), the amount of force required to accelerate a mass of one kilogram at a rate of one meter per second per second. In the specifications tables you will also find the force generated by hydraulic cylinders expressed as Hydraulic pulldown and Hydraulic pullback specified in lbf and kN units.

Conversion table This unit

Times

Equals

Length

This unit

Times

Equals

This unit

Times

Ounce (US fluid oz)

x 29.57

= ml

mph (mile/hour)

x 0.45

Equals

= m/s

x 0.4732

=l

mph (mile/hour)

x 1.61

= km/h

mm (millimeter)

x 0.001 (10-3)

=m

Pint (US liquid)

cm (centimeter)

x 0.01

=m

Quart (US liquid)

x 0.9463

=l

ft/s (foot/second)

x 18.29

= m/min

dm (decimeter)

x 0.1

=m

yd3 (cubic yard)

x 0.7646

= m3

ft/min (foot/minute)

x 0.3048

= m/min

km (kilometer)

x 1 000 (103)

=m

Force

in (inch)

x 25.4

= mm

kN (kilonewton)

x 1 000

=N

blow/min

x 0.017

= Hz

ft (feet)

x 0.305

=m

kp (kilopond)

x 9.81

=N

kHz (kiloHertz)

x 1 000

= Hz

yd (yard)

x 0.914

=m

kgf (kilogram force)

x 9.81

=N

rpm (rev/min)

x 0.01667

= r/s

mile

x 1609

=m

Ibf (pound force)

x 4.45

=N

degree/second

x 0.1667

= r/min

Power

Frequency

Torque (moment of force)

Pressure

J/s (joule/second)

x1

=W

kpm (kilopondmeter)

x 9.81

= Nm

bar

x 100

= kPa

Nm/s (newton meter/second)

x1

=W

Ibf•in (pound-force inch)

x 0.11

= Nm

bar

x 100 000 (105)

= Pa

kW (kilowatt)

x 1 000

=W

Ibf•ft (pound-force foot)

x 1.36

= Nm

kp/cm2

x 0.98

= bar

hk (metric horse power)

x 735.5

=W

Mass (commonly but incorrectly called weight)

atm (atmosphere)

x 1.01

= bar

hp (horsepower UK, US)

x 745.7

=W

g (gram)

psi (pounds/in2)

x 6.895

= kPa

t (tonnes, metric)

x 1 000

= kg

psi

x 0.06895

= bar

l (liter)

x 0.001

= m3

grain

x 0.0648

=g

Area

ml (milliliter)

x 0.001

=l

oz (ounce)

x 28.35

=g

mm2 (square mm)

x 0.000001 (10-6) = m2

dm (cubic decimeter)

x 1.0

=l

ozt (troy ounce)

x 31.10

=g

cm (square cm)

x 0.0001 (10-4)

= m2

cm (cubic decimeter)

x 1.0

= ml

lb (pound)

x 0.4536

= kg

in (square inches)

x 645

= mm2

mm (cubic millimeter)

x 0.001

= ml

ton (long, US)

x 1 016

= kg

ft (square feet)

x 0.0929

= m2

in (cubic inch)

x 16.39

= ml

ton (UK)

x 1 016

= kg

yd (square yard)

x 0.8361

= m2

ft (cubic feet)

x 28.316

=l

ton (short)

x 907

= kg

Acre

x 4 047

= m2

Imperial gallon

x 4.546

=l

Speed (velocity)

Square mile

x 2.590

= km2

US gallon

x 3.785

=l

km/h (kilometer/hour)

x 0.2777

= m/s

ha (hectare)

x 10 000

= m2

Ounce (Imp. fluid oz)

x 28.41

= ml

m/s (meter/sec)

x 3.6

= km/h

Equals

Divided by

This unit

Equals

Divided by

This unit

Equals

Divided by

This unit

Volume

3 3

3

3

3

118

x 0.001

= kg

2

2

2

2


bLASTHOLE dRILLS

Rotary blasthole drills Atlas Copco offers the most comprehensive line of rotary blasthole drills in the industry. With a multitude of configurations to choose from, you can find the perfect solution for your needs. Many models can be configured for either rotary or DTH drilling, and our blasthole products will drill holes from 4 inches to 16 inches in diameter. On the following pages, you will find basic specifications and brief descriptions of the standard and optional equipment available for each model. The different configurations of drill rigs and drill strings make it possible to find high-performing solutions for a variety of applications. Safety and ergonomic design with operator comfort and well-being in mind, as well as simplicity in maintenance, have been a focus for many years – and are still top priorities. When selecting your drill rig, you may have a choice between high-pressure compressors for DTH drilling or Blasthole Drilling in Open Pit Mining

low-pressure units for rotary drilling, and between diesel or electric power units. Depending on the drilling pattern and bench height, you can select between drills suitable for angle drilling or single- and multi-pass drilling. Some rig models, like the T4BH and the DM series that use conventional control systems, are well known throughout the mining community for their rugged and reliable designs.The newer Pit Viper series, with its more advanced designs, can be equipped with the RCS computerized network control system as an option, which offers possibilities for different levels of drill automation and communication. This is only a basic guide. Our product specialists around the world are prepared to provide you with the information you need to select the best drill and drill string package to suit your specific application.

119

bLASTHOLE dRILLS

120


bLASTHOLE dRILLS

DM25-SP

Technical data

The Atlas Copco DM25-SP surface blasthole drill is designed for rotary and fast down-the-hole drilling in the hardest of rock. The heavy-duty gear drive on this tough drill delivers precise control at variable speeds without compromising power, while the hydraulic motor feed system provides smooth, continuous bit loading and rapid feed speeds to reduce drilling costs. The DM25-SP has the option for a 40 ft (42.2 m) clean hole tower or a 50 ft (15.2 m) clean hole tower.

Standard equipment • • • • • • • • • • • • • • • • • • •

Spacious, thermal insulated and sound-attenuated cab Cab pressurizer/heater Hydraulically retractable dust hood with skirting Nine quartz halogen night lighting package Cooling package rated up to 125°F (52°C) ambient temperature Heavy duty engine silencer/muffler Separate air intake filters for engine and compressor Remote hydraulic tower pinning Hydraulically powered auxiliary chain wrench (DHD units only) 250-gallon (757 l) fuel tank Hydraulic spur gear and planetary drive rotary table with 0 to 170 RPM and a maximum torque of 3,500 lbf•ft Three 48 in. (1,219 mm) stroke leveling jacks with 18 in. (457 mm) pads 68,000 lb. (30,845 kg) GVW rated excavator-type undercarriage 19.7 in. (500 mm) wide triple bar grousers Separate air intake filters for engine and air compressor Reinforced rectangular steel track frame with oscillation yoke mounting Full length kelly bar and kelly sub Deck service catwalk with railings Back up alarm

Drilling Method

Rotary and DTH - Single pass

Hole Diameter

4 in - 7 in

102 mm - 178 mm

Hydraulic Pulldown

25,000 lbf

111 kN

Weight on bit

25,000 lb

11,300 kg

Hydraulic Pullback

25,000 lbf

111 kN

Single pass depth

40 ft or 50 ft 12.2 m or 15.2 m

Maximum hole depth

40 ft or 50 ft 12.2 m or 15.2 m

Feed speed

72 ft/min

21.9 m/min

Rotary table, torque

3,500 Ibf•ft

4.7 kNm

Estimated weight

62,000 lb

28 tonnes

Dimensions tower up (50 ft tower) Length

30 ft 6 in

9.3 m

Height

74 ft

22.6 m

Width

12 ft 8 in

3.9 m

Dimensions tower down (50 ft tower) Length

72 ft

21.9 m

Height

13 ft

4.0 m

Compressor range Low pressure, Rotary 900 cfm@110 psi 25.4 m3/[email protected] bar High pressure, DTH

900 cfm@350 psi 25.4 m3/min@24 bar

Engine (Tier III) Caterpillar

C15

425HP@1800RPM (LP 900)

Cummins

QSX15

425HP@1800RPM (LP 900)

Caterpillar

C15

525HP@1800RPM (HP 900)

Cummins

QSX15

525HP@1800RPM (HP 900)

Kelly specifications Hole depth*

Kelly diameter

Suggested bit diameters

Thread** size and type

40 ft (12.2 m)

2 7/8" (73 mm)

4" - 5 1/2"

2 3/8" IF

50 ft (15.2 m)

3 3/4" (95 mm)

5 1/2" - 7"

2 7/8" API

4 3/4" (121 mm)

5 7/8" - 7"

3 1/2" API

2 7/8" (73 mm)

4" - 5 1/2"

2 3/8" IF

3 3/4" (95 mm)

5 1/2" - 6 1/4"

2 7/8" API

4 3/4" (121 mm)

5 7/8" - 7"

3 1/2" API

* Clean hole ** All kellys have pin connections on both ends

High pressure DTH drilling Up to 6" DTH hammer and max. 7" bit diameter

DM25

Visit www.atlascopco.com/blastholedrills for more information


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bLASTHOLE dRILLS

122


bLASTHOLE dRILLS

DM30

Technical data

The Atlas Copco DM30 represents an ideal combination of versatility, economy, and power in blasthole drills. Atlas Copco drills have been hard at work serving the drilling community for over a century. Customers worldwide recognize Atlas Copco brand drills for quality, reliability, longevity and performance. The DM30 proudly carries on this tradition. Designed for quarrying and small mining applications, this versatile drill can be easily loaded onto a trailer and moved from one location to another.

Standard equipment

• • • • • • • • • • • • • • • • • • • •

Spacious, thermal insulated and sound-attenuated cab Cab pressurizer/heater/ventilator Hydraulically raised dust hood with skirting Nine quartz halogen night lighting package Auxiliary hoist for drill pipe and accessory handling Cooling package rated up to 125°F (52°C) ambient Heavy-duty engine silencer/muffler Separate air intake filters for engine and air compressor Remote hydraulic tower pinning Power indexed carousel for two 4, 4½ , or 5 in. OD x 30 ft. drill rods Remote hydraulic fork chuck for drill pipe breakout Hydraulically powered auxiliary chain wrench 250-gallon (946 l) fuel tank Rotaryhead with single fixed displacement motor with 0 to 100 RPM available, and a maximum torque of 5,400 lbf•ft Three 48 in. (1,219 mm) stroke leveling jacks 68,000 lb. (30,845 kg) GVW rated excavator-type undercarriage 19.7 in. (500 mm) wide triple bar grousers Reinforced rectangular steel track frame with oscillation yoke mounting Deck service catwalk with railings Back-up alarm

Drilling Method

Rotary and DTH - Multi pass

Hole Diameter

5 in - 6 3/4 in

127 mm - 171 mm

Hydraulic Pulldown

30,000 lbf

133 kN

Weight on bit

30,000 lb

13,600 kg

Hydraulic Pullback

10,000 lbf

44 kN

Single pass depth

26 ft

7.9 m

Maximum hole depth 150 ft

45 m

Feed speed

100 ft/min

30.5 m/min

Rotary head, torque

5,400 Ibf•ft

7.3 kNm

Estimated weight

60,000 lb

28 tonnes

Length

24 ft 4 in

7.4 m

Height

44 ft 4 in

13.5 m

Width

11 ft 10 in

3.6 m

Dimensions tower up

Dimensions tower down Length

42 ft 2 in

12.9 m

Height

14 ft 6 in

4.4 m

Compressor range Low pressure, Rotary

900 cfm@110 psi 25.4 m3/[email protected] bar

High pressure, DTH

900 cfm@350 psi 25.4 m3/min@24 bar


C15

425HP@1800RPM (LP 900)

Cummins

QSX15

425HP@1800RPM (LP 900)

Caterpillar

C15

525HP@1800RPM (HP 900)

Cummins

QSX15

525HP@1800RPM (HP 900)

Drill pipe specification Drill pipe diameter

Suggested bit diametersv - rotary

Thread

4" (102 mm)

5" – 6"

2 7/8" API

4 ½" (114 mm)

5 7/8" – 6 3/4"

3 1/2" API

5" (127 mm)

6 3/4"

3 1/2" API or BECO

High pressure DTH drilling Up to 6" DTH hammer and max. 6 ¾" bit diameter

DM30



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T4BH

Technical data

The Atlas Copco T4BH is synonymous with mobility, power, performance, and productivity. Mounted on a custom carrier, the T4BH is designed to perform in rough terrain and has been the leading blasthole drill in its class in the quarry and mining industries for over 35 years. The T4BH is a truck mounted, hydraulic tophead drive, multipass rotary drilling rig specifically designed for production blasthole drilling to depths of 150 ft. (45.7 m) with a 25 ft. (7.6 m) drill pipe change, optional 30 ft (9.1m) tower is also available with the 8 x 4 carrier option.

Standard equipment

• • • • • • • • • • • • • • • •

Spacious, thermal insulated sound-attenuated cab Six quartz halogen night lighting package Rectangular dust hood with skirting Auxiliary hoist for drill pipe and accessory handling Cooling package rated up to 125°F (52°C) ambient Heavy-duty engine silencer/muffler Separate air intake filters for engine and air compressor Power indexed carousel for five 4 ½ in OD x 25 ft pipe Remote hydraulic fork chuck for drill pipe breakout Hydraulically powered auxiliary chain wrench 205-gallon (776 l) fuel tank 4SV-2-10 spur gear 2-motor rotary tophead with 0 to 160 RPM, and maximum torque 6,500 lbf•ft Three 48 in. (1,219 mm) stroke leveling jacks Custom designed 3-axle carrier with 380 hp (283 kW) diesel engine, 10-speed transmission and 16 in. (406 mm) wide flange H-beam frame Remote tower pinning Back-up alarm

Drilling Method

DTH and Rotary - Multi pass

Hole Diameter

5 5/8 in - 9 7/8 in

149 mm - 254 mm

Hydraulic Pulldown

30,000 lbf

133 kN

Weight on bit

30,000 lb

13,600 kg

Hydraulic Pullback

22,000 lbf

97 kN

Single pass depth

22 ft 6 in or 27 ft 6 in

6.8 m or 8.4 m

Maximum hole depth*

147 ft 6 in or 177 ft 6 in

45 m or 54.1 m

Feed speed

60 ft/min

18.3 m/min

Rotary head, torque

6,500 Ibf•ft 7,165 Ibf•ft

8.8 kNm 9.7 kNm

Estimated weight

58,000 lb

26 tonnes


28 ft 8 in

8.7 m

Height

36 ft 6 in

11.1 m

Width

8 ft

2.4 m


35 ft 0 in

10.7 m

Height

13 ft 6 in

4.1 m

Compressor range High pressure, DTH

900 cfm@350 psi 25.4 m3/min@24 bar

High pressure, DTH

1070 cfm@350 psi 30.3 m3/min@24 bar

High pressure, DTH

1250 cfm@350 psi 35.4 m3/min@24 bar

Engine ( TierII, Tier III) 2

3

Cummins

QSX153

525HP@1800RPM (HP 900)

Cummins

QSX15

600HP@1800RPM (HP 1070)

Cummins

QSK19C2

3

760HP@1800RPM (HP 1250)


Suggested bit diameters Thread

4" (102 mm)

5 5/8" – 6"

2 7/8" API

4 1/2" (114 mm)

5 7/8" – 6 3/4"

3 1/2" API

5" (127 mm)

6 3/4" – 7 3/8"

3 1/2" API or BECO

5 1/2" (140 mm)

6 3/4" – 7 7/8"

3 1/2" BECO

6 1/4" (159 mm)

7 7/8" – 9"

4" BECO

7" (178 mm)

9"-9 7/8"

4 1/2" BECO

High pressure DTH drilling Up to 7" DTH hammer and max. 9" bit diameter * Maximum hole depth only achieved with certain pipe sizes and wall thicknesses

T4BH



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DM45/DM50 The Atlas Copco DM45 and DM50 are crawler mounted, hydraulic tophead drive, multi-pass rotary drilling rigs specifically designed for production rotary or DTH blasthole drilling to depths of 175 ft. (53.3 m) with a 30 ft. (9.1 m) drill pipe change.

Standard equipment

• • • • • • • • • • • • • • • • • • • • • •

Insulated cab with FOPS 80 dB(A) Cab pressurizer / ventilator / heater Nine quartz halogen night lighting package Dust hood with curtains and hydraulically raising dust flap Auxiliary hoist for drill pipe and accessory handling Heavy-duty engine silencer/muffler Separate air intake filters with quick release dust drop covers for engine and air compressor Gear indexing carousel for five 4½ in. x 30 ft. pipe Sliding hydraulic fork wrench for drill pipe breakout Hydraulically powered auxiliary chain wrench 350-gallon (1,324 L) fuel tank 4SV-2-10 two motor high speed rotary head with 0 to 160 RPM, and a maximum torque 7,200 lbf•ft 30 foot drill pipe change No-bump rod changer Ether injection Jack-up indicator lights Three 48 in. (1,219 mm) stroke leveling jacks 23.6 in. (600 mm) wide triple bar grousers Reinforced rectangular steel track frame with oscillation yoke Walkways and railings Remote tower pinning Back-up alarm

Technical data Drilling Method

Rotary and DTH Multi pass

Hole Diameter

5 7/8 in - 9 in

149 mm - 229 mm

Hydraulic Pulldown

45,000 lbf

200 kN

Weight on bit

45,000 lb

20,400 kg

Hydraulic Pullback

22,000 lbf

98 kN

Single pass depth

27 ft 5 in

Maximum hole depth* 175 ft Feed speed

8.5 m 53.3 m

146 ft/min Ibf•ft

44.5 m/min

Rotary head, torque

7,200

Estimated weight

77,000 lb 95,000 lb

35 tonnes 41 tonnes

Length

31 ft 10 in

9.7 m

Height

43 ft 7 in

13.3 m

Width

17 ft 2 in

5.23 m

9,76 kNm

Dimensions tower up


43 ft 7 in

13.3 m

Height

18 ft

5.5 m

Compressor range Low pressure, Rotary 900 cfm@110 psi 25.4 m3/[email protected] bar Low pressure, Rotary 1050 cfm@110 psi 29.7 m3/[email protected] bar Low pressure, Rotary 1200 cfm@110 psi 34.0 m3/[email protected] bar High pressure, DTH

900 cfm@350 psi 25.4 m3/min@24 bar

High pressure, DTH

1070 cfm@350 psi 30.3 m3/min@24 bar


C15

440HP@1800RPM (LP 900)

Cummins

QSX15

425HP@1800RPM (LP 900)

Caterpillar

C15

475HP@1800RPM (LP 1050)

Cummins

QSX15

475HP@1800RPM (LP 1050)

Caterpillar

C15

540HP@1800RPM (LP 1200)

Cummins

QSX15

530HP@1800RPM (LP 1200)

Caterpillar

C15

540HP@1800RPM (HP 900)

Cummins

QSX15

530HP@1800RPM (HP 900)

Caterpillar

C18

630HP@1800RPM (HP 1070)

Cummins

QSX15

600HP@1800RPM (HP 1070)



Thread

4 1/2" (114 mm)

5 7/8" – 6 3/4"

3 1/2" API

5" (127 mm)

6 3/4" – 7 3/8"

3 1/2" API or BECO

5 1/2" (140 mm)

6 3/4" – 7 7/8"

3 1/2" BECO

6 1/4" (159 mm)

7 7/8" – 9"

4" BECO

7" (178 mm)

9"

4 1/2" BECO

High pressure DTH drilling (DM45) Up to 6 1/2" DTH hammer and max. 8" bit diameter DM45

* Maximum hole depth only achieved with certain pipe sizes and wall thicknesses



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DML-SP The Atlas Copco DML-SP is a crawler-mounted, hydraulic table drive, single-pass rotary drilling rig, specifically designed for production blasthole drilling to depths of up to 60 ft. (18.3 m) in a single pass without a drill pipe change. Nominal hole size range is 6 to 9-7/8 in. (152 to 251 mm) for rotary bit applications. The DML-SP has the option for a 50 ft (15.2 m) clean hole tower or a 60 ft (18.3 m) clean hole tower.

Standard equipment • • • • • • • • • • • • • • • • • • • • •

Insulated cab with FOPS Cab pressurizer/heater Nine-quartz, halogen night lighting package Rectangular dust hood with skirting and hydraulically retractable front curtain Cooler package rated up to 125°F (52°C) ambient temperature Heavy duty engine silencer/muffler Separate air intake filters with quick release dust drop covers for engine and air compressor Hydraulically powered auxiliary chain wrench 350-gallon (1,324 l) fuel capacity Single motor rotary table with variable hydraulic motor (0-100 RPM) and a maximum torque of 7,500 lbf•ft Hydrostatic motor feed system Three 48 in. (121.9 cm) stroke leveling jacks 31.5 in. (800 mm) wide triple bar grousers Reinforced rectangular steel track frame with oscillation yoke mounting Walkways and deck railings Full depth kelly bar Kelly RPM tachometer on console Remote tower pinning Back-up Alarm Ether injection Jack-up indicator lights


Rotary and DTH - Single pass

Hole Diameter

6 in - 9 7/8 in

152 mm - 251 mm

Hydraulic Pulldown

54,000 lbf

240 kN

Weight on bit

54,000 lb

24,500 kg

Hydraulic Pullback

54,000 lbf

240 kN

Single pass depth

50 ft or 60 ft

15.2 m or 18.3 m

Maximum hole depth

50 ft or 60 ft

15.2 m or 18.3 m

Feed speed

100 ft/min

60 m/min

Rotary table, torque

7,500 Ibf•ft

10.2 kNm

Estimated weight

90,000 -100,000 lb

41 - 45 tonnes

Length (50 ft tower)

37 ft 6 in

11.4 m


37 ft 6 in

11.4 m

Height (50 ft tower)

71 ft 7 in

21.8 m


82 ft 7 in

25.2 m

Width

13 ft 10 in

4.1 m

Dimensions tower up

Dimensions tower down Length (50 ft tower)

68 ft

20.7 m


79 ft

24.1 m


19 ft 7 in

6.0 m


19 ft 7 in

6.0 m

Compressor range Low pressure rotary

1,200 cfm@110psi / 34.0 m3/[email protected] bar

Low pressure rotary


Low pressure rotary


High pressure, DTH

1,250 cfm@350psi / 35.4 m3/min@24 bar

Engine (2 TierII, 3 Tier III) 525HP@1800RPM (LP 1200)

Caterpillar C153 Cummins

QSX15

3


630HP@1800RPM (LP 1600)

QSX153

600HP@1800RPM (LP 1600) 800HP@1800RPM (LP 1900)


QSK19

2

755HP@1800RPM (LP 1900)

2

800HP@1800RPM (HP 1250)

QSK19C2

760HP@1800RPM (HP 1250)


525HP@1800RPM (LP 1200)

3

Kelly specifications Hole depth*

Kelly diameter


50 ft. (15.2 m) or 60 ft. (18.3 m)

4 3/4 in. (121 mm) 6" – 6 3/4"

Thread** size and type 3 1/2 in. Reg.

6 1/4 in. (159 mm) 7 7/8" – 9"

4 1/2 in. Reg.

7 in. (178 mm)

5 1/2 in. Reg.

9" – 9 7/8"

* Clean hole ** All kellys have pin connections on both ends.

High pressure DTH drilling Up to 7" DTH hammer and max. 8 7/8" bit diameter



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DML



The Atlas Copco DML is a crawler mounted, hydraulic tophead drive, multi-pass rotary drilling rig specifically designed for production blasthole drilling to depths of 175 ft. (53.3 m) with a 30 ft. (9.1 m) drill pipe change. An optional 35-ft. (10.7 m) steel change is also available to handle single pass drilling requirements. Various carousel capacities are also available for the 35-ft. (10.7 m) option.

Hole Diameter

5 7/8 in - 10 5/8 in

149 mm - 270 mm

Hydraulic Pulldown

60,000 lbf

267 kN

Weight on bit

60,000 lb

27,200 kg

Hydraulic Pullback

22,000 lbf

98 kN

Single pass depth

27 ft 5 in or 32 ft 5 in 8.5 m or 10 m

Maximum hole depth*

175 ft or 205 ft

Standard equipment

Feed speed

146 ft/min

0.7 m/s

Rotary head, torque

7,200 Ibf•ft

9.76 kNm

Estimated weight

87,000 - 110,000 lb

39.5 - 50 tonnes

• • • • • • • • • • • • • • • • • • • • • •

Insulated cab with FOPS Cab pressurizer / ventilator / heater Nine quartz halogen night lighting package Dust hood with curtains and hydraulically raising dust flap Auxiliary hoist for drill pipe and accessory handling Heavy-duty engine silencer/muffler Separate air intake filters with quick release dust drop covers for engine and air compressor Gear indexing carousel Sliding hydraulic fork wrench for drill pipe breakout Hydraulically powered auxiliary chain wrench 350-gallon (1,324 L) fuel tank 4SV-2-10 two motor high speed rotary head with 0 to 160 RPM, and a maximum torque of 7,200 lbf•ft 30 foot drill pipe change No-bump rod changer Ether injection Jack-up indicator lights Three 48 in. (1,219 mm) stroke leveling jacks 33.5 in. (850 mm) wide triple bar grousers Reinforced rectangular steel track frame with oscillation yoke Walkways and railings Remote tower pinning Back-up alarm

53.3 m or 62.5 m


31 ft 10 in

9.7 m

Height

43 ft 8 in

13.3 m

Width

16 ft 6 in

5m


43 ft 7 in

13.3 m

Height

17 ft 8 in

5.4 m


1,200 cfm@110 psi / 34.0 m3/[email protected] bar

Low pressure rotary


Low pressure rotary


High pressure, DTH (electric motor)

1,050 cfm@350 psi / 29.8 m3/min@24 bar

High pressure, DTH

1,250 cfm@350 psi / 35.4 m3/min@24 bar

High pressure, DTH

1,450 cfm@350 psi / 41 m3/min@24 bar

Engine (2Tier II, 3Tier III ) Caterpillar

C153

540HP@1800RPM (LP 1200)

Cummins

QSX153

530HP@1800RPM (LP 1200)

Caterpillar

C183

630HP@1800RPM (LP 1600)

Cummins

QSX15

Caterpillar

C272

800HP@1800RPM (LP 1900)

Cummins

QSK192

755HP@1800RPM (LP 1900)

Caterpillar

2

C27

800HP@1800RPM (HP 1250)

Cummins

QSK19C2

755HP@1800RPM (HP 1250)

Caterpillar

C272

800HP@2100RPM (HP 1450)

Cummins

QSK19C

760HP@2100RPM (HP 1450)

Weg motor

6808

700HP@50 – 60Hz (LP 1200 or HP1050)

600HP@1800RPM (LP 1600)

3

2



Thread

4 1/2" (114 mm)

5 7/8" – 6 3/4"

3 1/2" API

5" (127 mm)

6 3/4" – 7 3/8"

3 1/2" API or BECO

5 1/2" (140 mm)

6 3/4" – 7 7/8"

3 1/2" BECO

6 1/4" (159 mm)

7 7/8" – 9"

4" BECO

7" (178 mm)

9" – 9 7/8"

4 1/2" BECO

7 5/8" (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

High pressure DTH drilling Up to 7" DTH hammer and max. 8 7/8" bit diameter * Maximum hole depth only achieved with certain pipe sizes and wall thicknesses



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Pit Viper PV-235



The new Pit Viper series 235 blasthole drills offers several advanced options, like the RCS control system, remote tramming, auto levelling, and GPS navigation. The hydraulic system has been refined with load sensing and other features to reduce horsepower demand. There are several engine and compressor combinations available for either rotary or high pressure DTH drilling. The PV-235 can be supplied with any one of three towers - to drill 30 ft (9.1 m), 35 ft (10.7 m) or 40 ft (12.2 m) clean holes up to 9 7⁄8" (251 mm) in diameter.

Hole Diameter

6 in - 9 7/8 in

152 mm - 251 mm

Hydraulic Pulldown

60,000 lbf

267 kN

Weight on bit

65,000 lb

29,500 kg

Hydraulic Pullback

27,000 lbf

120 kN

Single pass depth

40, 35, 30 ft

12.2, 10.7, 9.1 m

Maximum hole depth*

240, 210, 180 ft

73.2, 64.0, 54.9 m

Feed speed

140 - 193 ft/min

0.7 - 1.0 m/s

Rotary head, torque

5,200 Ibf•ft 7,800 Ibf•ft

7.0 kNm 10.6 kNm

Standard equipment

Estimated weight

128,000 lb

58 tonnes

• • • • • • • • • • • • • • • • • • • • • •

Spacious thermal insulated cab with FOPS and noise abated less than 80 dB(A) Cab pressurizer / ventilator / heater Twelve quartz halogen night lighting package Dust hood with curtains and hydraulically raising dust flap Auxiliary hoist for drill pipe and accessory handling Heavy duty engine silencer / muffler Separate air intake filters with rubber dust evacuator for engine and air compressors Gear indexing carousel for 5 ½ in x 30 ft pipe Sliding hydraulic fork wrench for drill pipe breakout Hydraulically powered auxiliary breakout wrench 450 gallon fuel tank (1,700 l) 4SV-2-10 two motor high speed rotary head with 0-160 RPM, and a maximum torque of 7,200 lbf•ft 30 ft drill pipe changer No-bump rod changer Battery and starter lockable master-switches with jump start receptacle Jack-up indicator lights Four 48 in (1.2 m) stroke leveling jacks Triple bar grousers 33.5 in (850 mm) wide Reinforced rectangular steel track frame with oscillation yoke Walkways and railings Remote tower pinning Back-up alarm


34 ft 2 in

10.4 m

Height

52 ft 8 in

16 m

Width

14 ft 6 in

4.4 m


53 ft 4 in

16.2 m

Height

18 ft 8 in

5.7 m



Low pressure rotary


Low pressure rotary


High pressure, DTH

1,250 cfm@350 psi / 35.4 m3/min@24 bar

High pressure, DTH

1,450 cfm@350 psi / 41.0 m3/min@24 bar

High pressure, DTH (electric motor)

1,050 cfm@350 psi / 29.8 m3/min@24 bar

Engine (3Tier III, 2Tier II) 540HP@1800RPM (LP 1200)

Caterpillar

C153

Cummins

QSX15

530HP@1800RPM (LP 1200)

Caterpillar

C183

630HP@1800RPM (LP 1600)

Cummins

QSX153

600HP@1800RPM (LP 1600)

Caterpillar

C27

800HP@1800RPM (LP 1900 or HP 1250)

Cummins

QSK192

755HP@1800RPM (LP 1900 or HP 1250)

Caterpillar

C272

800HP@2100RPM (HP 1450)

Cummins

QSK19

WEG

6808

3

2

2

760HP@2100RPM (HP 1450) 700HP@50-60 Hz

Drill pipe specification

PV-235

Drill pipe diameter


Thread

4 1/2" (114 mm)

6" – 6 3/4"

3" BECO

5" (127 mm)

6 3/4" – 7 3/8"

3 1/2" BECO

5 1/2" (140 mm)

6 3/4" – 7 7/8"

3 1/2" BECO

6 1/4 (159 mm)

7 7/8" – 9"

4" BECO

7" (178 mm)

9"

4 1/2" BECO

7 5/8" (194 mm)

9 7/8"

5 1/4" BECO

8" (203 mm)

9 7/8"

5 1/4" BECO

High pressure DTH drilling Up to 7" DTH hammer and max. 8 7/8" bit diameter * Maximum hole depth only achieved with certain pipe sizes and wall thicknesses



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Pit Viper PV-271


Rotary and DTH – Single pass

The PV-271 is designed to handle 6-¼" up to 8- ⁄ " drill rods. The cable feed system utilizes a dual rod/ dual piston cylinder and offers high feed speeds for increased productivity. The PV-271 offers a 55 ft singlepass tower with a total depth capacity of 105 ft through a 2-rod carousel with 25 ft rods. It has an option to be delivered with the RCS computerized rig control system, incorporating functions like; remote tramming, auto levelling, auto drilling, and GPS navigation.

Hole Diameter

6 3/4 in - 10 5/8 in

171 mm - 270 mm

Hydraulic Pulldown

70,000 lbf

311 kN

Weight on bit

75,000 lb

34,000 kg

Hydraulic Pullback

35,000 lbf

156 kN

Single pass depth

55 ft

16.8 m

Maximum hole depth

105 ft

32 m

Feed speed

127 ft/min

0.6 m/s

Standard equipment

Rotary head, torque

8,700 Ibf•ft

11.8 kNm

Estimated weight

185,000 lb

84 tonnes

Length

41 ft 3 in

12.6 m

Height

87 ft

26.5 m

Width

18 ft 4 in

5.6 m

58

• • • • • • • • • • • • • • • • • • •

Insulated, pressurized, air conditioned cab with tinted glass and suspension operator seat Caterpillar 345XL undercarriage with hydraulic track tensioners Hydraulic cylinders driven cable feed system Hydraulic motor driven rotary head; maximum 8,700 lbf•ft torque; speed range 0 - 150 rpm Rotary head tachometer on operator console Remote hydraulic tower pinning Two-rod carousel for 6 ¼" to 8- 5⁄8" drill rods "No-bump" rod changer Hydraulically powered breakout wrench (fork chuck) Hands Free auxiliary hydraulic chain wrench 8,000 lb (3,629 kg) capacity auxiliary hoist Hydraulically retractable dust curtains Cooling package Separate air intake filters for engine and air compressor Wide flange structural steel beam frame with oscillation yoke mounting Hydraulic Test Station 12-light night lighting package-70 watt halogen Full deck service catwalks and railings Two 48" (1.2 m) and one 60" (1.52 m) stroke leveling jacks

Dimensions tower up


83 ft 7 in

25.5 m

Height

22 ft 1 in

6.7 m



Low pressure rotary


High pressure, DTH

1,450 cfm@350 psi / 41.1 m3/min@24 bar

Engine (Tier ll) Caterpillar

C27

800HP@1800RPM (LP 1900)

Cummins

QSK19

755HP@1800RPM (LP 1900)

Caterpillar

C32

950HP@1800RPM (LP 2600)

Caterpillar

C27

800HP@2100RPM (HP 1450)

Cummins

QSK19

755HP@2100RPM (HP 1450)

Weg motor

6808

700HP / 671 kW@ 50 or 60Hz

Weg motor

6811

900HP / 671 kW@ 50 or 60Hz



Thread

6 1/4" (159 mm)

6 3/4" – 9"

4" BECO

7" (178 mm)

9" – 9 7/8"

4 1/2" BECO

7 5/8" (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8" (203 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8 5/8" (219 mm)

10 5/8"

6" BECO


PV-271



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Pit Viper PV-275


Rotary and DTH – Multi pass

The PV-275 is designed to handle 6-¼" up to 8- ⁄ " drill rods. The cable feed system utilizes a dual rod/dual piston cylinder and offers high feed speeds for increased productivity. The PV-275 offers a multi-pass tower with 195-ft depth capacity through a 4-rod carousel with 40-ft rods. It has an option to be delivered with the RCS computerized rig control system, incorporating functions like; remote tramming, auto levelling, auto drilling, and GPS navigation.

Hole Diameter

6 3/4 in - 10 5/8 in

171 mm - 270 mm

Hydraulic Pulldown

70,000 lbf

311 kN

Weight on bit

75,000 lb

34,000 kg

Hydraulic Pullback

35,000 lbf

156 kN

Single pass depth

37 ft

11.3 m

Maximum hole depth

195 ft

59.4 m

Feed speed

127 ft/min

0.6 m/s

Standard equipment

Rotary head, torque

8,700 Ibf•ft

11.8 kNm

Estimated weight

185,000 lb

84 tonnes

Length

41 ft 6 in

12.6 m

Height

67 ft

20.4 m

Width

18 ft 4 in

5.6 m

58

• • • • • • • • • • • • • • • • • • • •

Insulated, pressurized, air conditioned cab with tinted glass and suspension operator seat Caterpillar 345SL undercarriage with hydraulic track tensioners Hydraulic cylinders driven cable feed system Hydraulic motor driven rotary head; maximum 8,700 lbf•ft (11,800 Nm) torque; speed range 0 – 150 rpm Rotary head tachometer on operator console Remote hydraulic tower pinning Four-rod carousel for 6 ¼" to 8-5⁄8" drill rods "No-bump" rod changer Hydraulically powered breakout wrench (fork chuck) Hands Free auxiliary hydraulic wrench 8,000 lb (3,629 kg) capacity auxiliary hoist Hydraulically retractable dust curtains Hydraulic Test Station Two 48" (1.2 m) and one 60" (1.52 m) stroke leveling jacks Cooling package 350 U.S. gallon (1,325 L) fuel tank Separate air intake filters for engine and air compressor Wide flange structural steel beam frame with oscillation yoke mounting 12-light night lighting package- 70 watt halogen Full deck service catwalks and railings

Dimensions tower up


63 ft 6 in

19.4 m

Height

22 ft 1 in

6.7 m



Low pressure rotary


High pressure, DTH

1,450 cfm@350 psi / 41.1 m3/min@24 bar


C27

800HP@1800RPM (LP 1900)

Cummins

QSK19

755HP@1800RPM (LP 1900)

Caterpillar

C32

950HP@1800RPM (LP 2600)

Caterpillar

C27

800HP@2100RPM (HP 1450)

Cummins

QSK19

755HP@2100RPM (HP 1450)

Weg motor

6808

700HP / 671 kW@ 50 or 60Hz

Weg motor

6811

900HP / 671 kW@ 50 or 60Hz



Thread

6 1/4" (159 mm)

6 3/4" – 9"

4" BECO

7" (178 mm)

9" – 9 7/8"

4 1/2" BECO

7 5/8" (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8" (203 mm)

9 7/8" – 11"

5 1/4" BECO

8 5/8" (219 mm)

10 5/8"

6" BECO


PV-275



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138


bLASTHOLE dRILLS

DM-M3

Technical data

The Atlas Copco DM-M3 is a crawler-mounted, hydraulic tophead drive, multi-pass rotary drilling rig specifically designed for the blasthole drilling of 9-7⁄8 in. (251 mm) to 12-¼ in. (311 mm) diameter holes. The on-board depth capability is up to 240 feet (73 m) when using 8-5⁄8 in. diameter (219 mm) drill pipe and a 5-rod carousel. Standard drill pipe length is 40 feet (12.2 m). Hydraulic pulldown is featuring a patented hydrostatic, closedloop system acting through twin, double-rod hydraulic cylinders and cable.

Standard equipment

• • • • • • • • • • • • • • • • • •

Insulated, pressurized FOPS cab with heater Rotary screw 2600 CFM @ 110 psi air compressor Caterpillar C32 diesel engine (950 HP at 1800 rpm) Six-light, 70 watt quartz-halogen night lighting system Cab and ladder access lights plus dust curtain light Cooling package Remote hydraulic tower pinning Auxiliary hoist of 8,000 lb (3,600 kg) capacity with lifting bail Hydraulically-actuated, drill pipe carousel internal to tower for 4 drill pipe or 5 for 8- 5/8" in. diameter 40 ft. Hydraulic sliding fork chuck breakout with auxiliary hydraulic wrench 650 U.S. gallon (2,460 L) fuel capacity Wide flange structural steel "I" beam main frame with oscillation yoke mounting Separate three-stage air intake filters for engine and compressor Rotary head tachometer Three hydraulic leveling jacks and "jacks-up" indicator in cab Hydraulically actuated rod support arm to align drill pipe during rod changing operations and when using the angle drill option Full walkways and railings 35.5 in (900 mm) wide, triple bar replaceble grouser pads

Drilling Method

Rotary - Multi pass

Hole Diameter

9 7/8 in - 12 1/4 in

251 mm - 311 mm

Hydraulic Pulldown

90,000 lbf

400 kN

Weight on bit

90,000 lb

40,800 kg

Hydraulic Pullback

41,500 lbf

185 kN

Single pass depth

37 ft

11.3 m

Maximum hole depth

200 - 240 ft

61 - 73.2 m

Feed speed

144 ft/min

0.7 m/s

Rotary head, torque

10,183 Ibf•ft

13.8 kNm

Estimated weight

230,00 lb

104 tonnes

Length

40 ft 5 in

12.3 m

Height

67 ft

20.4 m

Width

18 ft 11 in

5.8 m

Dimensions tower up


66 ft 6 in

20.3 m

Height

23 ft 9 in

7.2 m


2600 cfm@110 psi / 73.6 m³/[email protected] Bar


C32

950HP / 709 kW@1800RPM (LP 2600)

Cummins

QST30

950HP / 709 kW@1800RPM (LP 2600)

Weg motor

6811

900HP / 671 kW@ 50 or 60Hz (LP 2600)



Thread

7 5/8" (194 mm)

9 7/8" – 10 5/8"

5 1/4" BECO

8 5/8" (219 mm)

10 5/8" - 11"

6" BECO

9 1/4" (235 mm)

11" – 12 1/4"

6" BECO

10 3/4" (273 mm)

12 1/4"

8" BECO

DM-M3



139

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140


bLASTHOLE dRILLS

Pit Viper PV-351

Technical data

The Pit Viper 351 is a crawler-mounted, hydraulic tophead drive, multi-pass rotary drilling rig specifically designed for the blasthole drilling of 10-5⁄8 " to 16 in diameter holes. It has a single-pass depth capability of 65’ (20 m) with total depth capability of 135’ (41 m). Its hydraulic driven cable feed system is capable of 125,000 lbf. (511 kN) of bit loading. Due to the light weight of the cable feed system the PV-351 can operate with a “live tower”. A patented automatic tensioning system is eliminating down time for cable adjustments. It has several advanced options like an auto drilling system, auto levelling, remote tramming, and GPS navigation.

Standard equipment

• • • • • • • • • • • • • • • • • • • • • • •

RCS rig control system, computerized network Insulated, air conditioned cab 3000 CFM (84.9 m3/min) @ 110 psig (7.6 bar) air compressor Caterpillar 385 Custom undercarriage with hydraulic propel and automatic hydraulic track tensioning Hydraulic cylinder driven cable feed system Hydraulic motor driven rotary head Two rod carousel for 8-5/8" to 13-3/8" diameter x 35’ drill pipe “No-bump” rod changer Hydraulically powered breakout wrench (fork chuck) Hands Free auxiliary hydraulic chain wrench 12,000 lb (5440 kg) capacity auxiliary hoist Hydraulically retractable dust curtains Four 72 inch (1.83 m) stroke leveling jacks Cooling package 1200 U.S. gallon (4545 L) fuel tank Separate air intake filters for engine and air compressor Wide flange structural steel I-beam frame with oscillation yoke mounting Full deck service catwalks and railings Automatic lubrication system Nordic Night light package Attention horn, propel alarm Ground level shutdowns Decking in tower (when horizontal) above rod changer

Drilling Method

Rotary - Single pass

Hole Diameter

10 5/8 in - 16 in

270 mm - 406 mm

Hydraulic Pulldown

120,000 lbf

534 kN

Weight on bit

125,000 Ib

56,700 kg

Hydraulic Pullback

60,000 lbf

267 kN

Single pass depth

65 ft

19.8 m

Maximum hole depth

135 ft

41.1 m

Feed speed

127 - 158 ft/min

0.6 - 0.8 m/s

Rotary head, torque

19,000 Ibf•ft

25.7 kNm

Estimated weight

385,000 lb 415,000 lb

175 tonnes 188 tonnes

Length

53 ft 10 in

16.4 m

Height

103 ft 9 in

31.6 m

Width

26 ft 8 1/2 in

8.1 m

Dimensions tower up


98 ft

29.9 m

Height

27 ft 11 in

8.5 m


3,000 cfm@110psi / 84.9m3/[email protected] bar

Low pressure rotary (electric motor)


Low pressure rotary


Engine (Tier l) Caterpillar

3512

1650HP@1800RPM

Cummins

QSK45

1500HP@1800RPM

Weg motor

6811

1400HP / 1044kW@ 50 or 60 Hz



Thread

8 5/8" (219 mm)

10 5/8" - 11"

6" BECO

9 1/4" (235 mm)

11" – 12 1/4"

6" BECO

10 3/4" (273 mm)

12 1/4" - 13"

8" BECO

12 3/4" (324 mm)

15" – 16"

8" BECO

13 3/8" (340 mm)

16"

10" BECO

PITVIPER 351

atlascopco.com



141

bLASTHOLE dRILLS

142


DRILL RIG OPTIONS

Electric power pack

As an alternative to a diesel engine as the main source of power, several drill models can be configured with an electric power package, consisting of an electric WEG motor, starter and transformer. Electric versions are usually less costly to operate due to fewer lubricants, having an integrated cooling system, and no diesel fuel costs. In some cases, the operating cost advantage will in one year cover the additional investment cost for ordering an electric version. The service life of an electric motor is considerably longer than for an equivalent diesel engine, and has quieter operation. Weg motor options are available for: DML, DM-M3, PV-235, PV-271, PV-275, PV-351

Four jack configuration Stability in the set up of the drill rig is important for the drilling operations. All drill rigs are provided with hydraulic leveling jacks, as a basic “tripod arrangement” some models have an option of a four jack arrangement where the two non drilling end jacks are tied together acting as one outrigger. Available for: DML, DM-M3, PV-271, PV-275 Standard equipment for PV-235 and PV-351 Blasthole Drilling in Open Pit Mining

143

DRILL RIG OPTIONS

Cold weather operation • To secure trouble-free operation and a pleasant operator’s working environment, there are several cold weather options available including: additional cab heater, hydraulic oil and diesel engine heating, tank heaters, arctic hoses and cold weather fluids. • A well insulated and heated water injection system is available. • Gen-sets are available for some models of drill rigs • Fully utilized these options allow the drill rigs to operate in arctic conditions.

Angle drilling package The Atlas Copco advanced angle drilling package allows the tower to be positioned from the vertical in increments of 5 degrees. All controls for positioning are located at the operators control console inside the cab. This system changes the pivot point on the tower to drill deck level and ensures that the hole will always collar within the dust hood. This design also provides for stability and ensures that a minimum length of the drill pipe will be unsupported between the centralizer and the collar. Good stability and guidance of the drill string during collaring and drilling will reduce hole deviation. High precision in drilling and blasting will improve fragmentation and contribute to lowering overall production costs Available for: PV-235, PV-271, PV-275, DM-M3, PV-351 Variations of the angle drill package are available on all other models

144


DRILL RIG OPTIONS

Auto thread lubrication system The system includes a cab activated button that initiates flow of grease through a pneumatic pump to a nozzle. The nozzle is located on the drill table, and sprays the grease at the pipe joint threads. This helps to extend the life of your pipe threads when changing rods.

Central lubrication system The Quicklube lubrication system is designed to provide a relatively simple and inexpensive method of centralizing and automating the lubrication of machinery bearings. The system dispenses small measured amounts of lubricant at frequent intervals while the machine is operating. With a fully automated system, the lubricant is supplied by a electric pump through one or more distribution blocks to each point covered by the system. Even those hard to reach are assured of being properly lubricated and purged of contaminants. Up to 300 lubrication points can be served, depending on the length of the hose. • Reliably distributed lubricant in predetermined amounts • Delivers lubricant to the connected lubricant points in a safe manner. • Each lubrication circuit is equipped with a safety valve that holds the pressure within permissible values. • If there is a block in a lubrication circuit, lubricant will leak from the safety valve. • Works through lubrication cycles (interval time, propagation time and load time) Can be used in cold weather applications if special low temperature grease is used. Blasthole Drilling in Open Pit Mining

145

DRILL RIG OPTIONS

Central hydraulic test station The central hydraulic test station allows for testing of component pressures. A standard test fitting gauge can be used and plugged in into the desired port for reading of the system pressure. The hydraulic test station is mounted on the deck for easy accessibility. Available for: T4BH, DM45, DML, PV-235, DM-M3 Standard equipment for PV-271, PV-275 (not required for RCS rigs - electronic sensors are included in the RCS system)

Fire suppression system A dry-chemical fire suppression system can be provided with manual activation points. The system is provided with canister(s) that are located on the deck of the machine. The fire suppression canister contain a dry chemical fire suppressant which utilizes a nitrogen cartridge for the pneumatic actuator. Several discharge nozzles located throughout the machine will spray the suppressant when the system is activated. This fire extinguisher agents is rated for extinguishing type A (trash/wood), type B (liquids) and type C (electrical equipment) fires. The fire suppression canister can be recharged as needed.

146


DRILL RIG OPTIONS

Water injection system The water injection system injects a regulated quantity of water into the air flow going to the drill pipe. The water content in the air-flushing suppresses the dust created by the drilling operation. The water injection system has a hydraulic motor drive, and is operated from the cab control system. There are several sizes of water injection systems available, and the injection tanks are either mounted within the frame or on the deck to ensure the drilling water requirements are met.

Dust collector Different sized “no visible emission” dry dust collectors are available. The design features a pleated paper element type fan/filter unit. Interval flushing is controlled by an electronic timer. A vacuum hose allows the fan/ filter unit to draw the dust out of the collection area. The dust is removed from the air stream as the air flows through the pleated paper filter elements. Heavy cuttings are contained around the hole. Operation of the dust collector is controlled from the cab control system.


147

DRILL RIG OPTIONS

Fast service system The fast service system consists of ground level, quick connect fittings for fill and evacuation of fuel, hydraulic oil, engine oil, compressor oil, engine coolant, and water (on some models).

Ground level shut down All rigs are provided with a standard emergency shutdown button mounted in the cab. As an option, one or several additional ground level shutdown buttons can be provided for mounting outside of the cab. By pressing the ground level shutdown button, the power to the engine is disconnected.

Racor fuel filter The Racor fuel filter is specifically designed to separate out any water that may be in the fuel lines, and a Racor fuel filter with heater option as shown is available for some models.

148


DRILL RIG OPTIONS

Remote tramming system The optional remote tramming system offers the operator the ability to move the rig from a drive pendant which can be worn on the operator’s shoulders. The remote tram pendant is connected to the rig by a cord, and is operated by similar joysticks as these used on the operator’s panel in the cab. Available for: DM45, DML, PV-235, PV-271, PV-275, (non RCS rigs), DM-M3

Remote control unit with cord connection.

Radio remote control Wireless remote tramming function allows the operator to tram a Pit Viper from the bench within a 60 m distance.

Information from the OU unit is radio transmitted to the RRC Machine Unit and executed by the RCS.

The RRC radio remote control Operator’s Unit (OU unit) with all controls and indicators ( for drill rigs with RCS option).

Available for: Pit Viper with RCS (see page 25 for details on RCS package)

Video camera system For improved safety and visibility around the drill rig an optional video camera system can be installed. The system consists of three or four rig mounted video cameras and a LCD display screen mounted inside the cab. Each camera has a motorized lens cover for protection, and contains a heater which automatically turns on when the temperature falls below 50° F (10°C). The cameras are installed in water resistant housings, complete with illuminators for low light conditions. The camera image device is an interline – transfer 0 type CDC, with a picture resolution of 270,000 pixels (horizontal resolution of 380 TV lines and a vertical resolution of 350 TV lines The monitor is a 6.8" LCD screen with an auto dimmer. Screen resolution is 270.000 pixels, and screen controls include: bright, contrast, color, tint, image selectable, auto scan time and scale (on/off) Available for: PV-235, PV-271, PV-275, PV-351 Blasthole Drilling in Open Pit Mining

149

DRILL RIG OPTIONS

Stereo radio with CD player The operator’s cab can be equipped with a stereo system with AM/FM radio, CD player, mp3 jack and speakers. The package also includes a battery equalizer for 24V to 12V DC conversion. Available for: DM45, DML, PV-235, PV-271, PV-275, DM-M3, PV-351

Engine pre-lube system Special engine pre-lube assembly systems are available both for Cummins and CAT diesel engines. The engine pre-lube, lubes the valve zone prior to engine startup, giving the benefit of less wear and tear on the engine over time Available for: DM45, DML, PV-235, PV-271, PV-275, DM-M3, PV-351, Standard equipment for PV-351(Cummins)

Towing package Tow hooks or a tow bar mounted on the non drill end of the rig allow for towing. Available for: DM45, DML, PV-235, PV-271, PV-275, DM-M3, PV-351

150


DRILL RIG OPTIONS

High intensity discharge lights The high intensity discharge (HID) night light package consists of upgrading the standard halogen lights to Xenon 24V, 35 Watt lamps. With this upgrade the HID lamps will be mounted in the standard lamp locations. The HID lamps have great luminous intensity and a color mimicking natural daylight. These lamps are designed specifically for forestry, mining and earth moving applications, and are designed to have low power consumption. Lights can be turned on when the engine is on or off.

Sodium 240 Volt night light package The 240 VAC night light package consists of additional 400 Watt high pressure sodium lights and additional 150 Watt high pressure sodium lights. These lights are installed in addition to the standard light package on the rig and require power from an external 240 VAC power source (like an optional gen-set). Available for: DM45, DML, PV-271, PV-275, DM-M3 Standard equipment for PV-351 Electric


151

DRILL RIG OPTIONS

Buddy seat If an additional seat is required in the cab, a fold-up buddy seat can be mounted inside one of the cabin walls. Available for: DM45, DML, PV-271, PV-275 Standard seat: PV-235, PV-351

Torque limit control Rotational torque limit control is standard on high pressure drill rigs, and is an option available for low pressure rigs. The torque limit gauge and controller are mounted in the cab and operate an electrically controlled remote valve. Torque limit control is used to limit the rotation pressure within the closed loop rotation circuit. Available for: DM25, DM30, DM45, DML, PV-235, PV-271, PV-275

Cab sunshades Pull down, fabric sunshades located on all windows are available. Available for: DM45, DML, PV-235, PV-271, PV-275, DM-M3, PV-351

152


DRILL RIG OPTIONS


153

Rotary drilling TOOLS

Tricone rotary blasthole drilling

Introduction

Tricone drilling can move much more material in a given amount of time than DTH drilling due to the generally larger diameters used, but Tricone drilling may be a less “ore grade sensitive” method due to larger bit diameters and therefore greater hole burden and spacings used. Ultimately, the mine’s “production cost” is the economic driver: at the end of the day, which method gives the lowest COST PER TON of material blasted?

An impressive legacy

Atlas Copco Secoroc LLC. traces its beginnings back to Howard Hughes, Sr., inventor of the first two-cone rotary drill bit for rock in 1909. “Our purpose is to never be satisfied but will continue, with the help of our experienced engineers, to anticipate the requirements of the drilling industry.” The words spoken by Mr. Hughes are valid at Atlas Copco Secoroc LLC today. Howard Hughes, Sr. left behind an impressive inventor’s legacy, having held 73 distinct patents. The company continued to be a leader in development, with the introduction of the first TriconeTM rock bit with inter-fitting teeth in 1933, and the first Tungsten Carbide Insert rockbits in 1951.

Lowering our Customers Total Drilling Cost (TDC)

Atlas Copco Secoroc LLC is dedicated to reducing the customer’s total drilling costs while maintaining the highest standards of quality. Atlas Copco Secoroc LLC has repeatedly shown customers that a better bit, though more expensive, actually reduces the cost of the drilled hole. When a mining engineer or a purchasing group takes into account the total cost of operating a drill, it is easy to see that the best way to cut costs is to drill the hole faster. Our goal is not to just meet your expectations, but to exceed them. As part of our commitment to continuous improvement, we constantly look for ways to make our products drill faster and more efficiently.

Tricones or DTH?

How do you decide on which drilling method to use, Rotary Tricone drilling, or Down The Hole hammer drilling? Each has several factors in its favor. DTH drilling in hard ground generally has higher penetration rates than Tricone drilling, and exerts less wear and tear on the drill because heavy “pulldown” forces are not used with DTH. But it is much more labor, consumables, and inventory intensive than tricone drilling. In soft ground, DTH drilling tends to be problematic. DTH loses its penetration rate advantage at 9 to 10 inch diameter (229 - 254 mm) in “hard” rock.

154

Let’s consider this example, for a straight forward “rock removal” scenario: • 12 1/4” Tricone bit and suitable drill • 100 feet (30.5 m) per hour penetration rate • 50 foot (15.2 m) bench height, plus subdrill • US$300/hour drill operating cost • 9” DTH and suitable drill • 50 foot (15.2 m) bench height, plus subdrill • 125 feet (38.1 m) per hour penetration rate • US$200/hour drill operating cost

Which method has the lowest cost per ton?

Using the Hustrulid blasting calculations presented in the various Atlas Copco Academy sessions (which calculate burden, spacing, subdrill, and stemming based on hole size, face height, and rock and explosive SG), we see the following production costs: 12 ¼" Tricone & Big drill

9" DTH & Small drill

$300

CPH

$200

100

ROP

125

5676.9

Tons per hour produced

3970.2

1

Drill required for tonnage

1.430

$0.053

Op cost/ton/drill

$0.050

$0.053

Actual cost/drilled ton

$0.072

In this example, DTH drilling is almost 50% more costly than using Tricones. In fact, it takes another 17% increase in Rate of Penetration, to 146 feet/hour, for the DTH method to equal the Cost per Drilled Ton of the Tricone method. Depending on the commodity mined, the geometry of the mining benches, the tonnage production rate needed, etc., it is advised that rotary Tricone drilling always be investigated as a more cost effective way to correctly serve the customer.





Elements of a rock bit

155



Bit elements

Cones

Carbide Insert Rows

Cones make up the cutting elements of the rock bit and are comprised of the following:

A. Nose B. Inner C. Next to Gage D. Gage E. Gage Bevel

1. Tungsten Carbide Inserts - which are pressed into the softer steel material with interference fit to hold item in place. 2. Cone Thrust Button - Made of a wear resistant material used to take axial bearing loads. 3. Outer Cone Shell - Insert land’s and cone grooves. 4. Cone Bore - Internal ball and roller bearing races.

156




Bit elements

Lugs Coupled in threes, by 120º to form the bit body and the pin connection, the lugs are machined to hold the nozzles and a journal-bearing surface.

Nozzles Nozzles are used to create back-pressure in the bit to force air through the bearing airways and increase the “air-blast” force to remove and flush cuttings from the bottom of the hole. Too large of a nozzle will cause insufficient volumes of air to be delivered to the bearings, while too small of a nozzle will increase the back-pressure above the compressor modulation setting. When the compressor’s modulation setting is reached, it will then reduce it’s volume output causing a decrease in (air?) volume going to the bit.


157



Tricone bit inserts

Inserts are the actual physical elements that spall and break the rock. Inserts are made from tungsten carbide powder and a cobalt binder material, which is pressed into the designed shape then sintered. Depending on the application, the tungsten carbide inserts in a given bit will have a shape and physical properties best suited for the rock being drilled.

Conical

Round top

Chisel

90º Chisel or trimmer

Ogive

Wedge crested chisel

Super Scoop

Serrated flat top

The conical insert is used primarily in medium/medium-hard rock. It is designated in the bit nomenclature with a C.

The chisel insert is used in soft/ medium-soft rock. It is the standard insert in soft bits (40’s & 50’s) and is designated with an F in the bit nomenclature.

The ogive insert is used in areas where the aggressiveness of the conical insert is required with additional toughess. The ogive is designated as an O in the bit nomenclature.

The super scoop is used in very soft rock. With the patented offset tip, digging and gouging help penetrate in sticky materials. The super scoop is designated with an S in the bit nomenclature.

158

The ovoid or round top insert is used in the hardest formations. Its blunt geometry gives it the most fracture resistant design. The round top is the standard insert in hard bits (60’s 70’s & 80’s) and is designated with an N in the bit nomenclature.

The trimmer is used specifically in the MAGNT product line. It enhances the gage rows ability to cut the bore hole wall. The MAGNT feature is used in soft to medium brittle rock formations.

Wedge crested chisel inserts are used exclusively on the gage rows of very soft to hard bits (40’s through 60’s). This shape gives a fracture resistant insert that is much tougher than concial or regular chisel inserts on gage.

Serrated flat top inserts are used on shirttail lips and along the lug as “armor” to protect against shirttail and lug wear.




Nomenclature

Atlas Copco Secoroc LLC uses the IADC (International Association of Drilling Contractors) code along with the product line and added bit features to help describe the bit. The IADC code is a three numbered system to classify the hardness and type for all roller cone rock bits.

Product lines: •

MAG NT – Maximum Active Gage (MAG)/New Technology (NT). Used in soft/medium brittle material. Features include enhanced erosion resistance and new bearing geometries.

First digit – Identifies the bit type and major hardness class:

• •

HD NT – Hard Drilling (HD)/New Technology (NT). Medium hard to hard formation bits, with new carbide grades, aggressive cutting structures and enhanced bearings. eM – epsilon technology evolved from the MAG product line. Wide variety of drilling applications using streamlined lugs for greater bailing area and allowing rapid evacuation of cuttings. Balanced cut ting structures for improved bearing loading, lowered carbide stress and higher capacity bearings for longer life.

•

eH – epsilon technology evolved from the HD product line. Wide variety of drilling applications using streamlined lugs for greater bailing area and allowing rapid evacuation of cuttings. Balanced cutting struc tures for improved bearing loading, lowered carbide stress and higher capacity bearings for longer life.

1 – Steel Tooth for soft formations 2 – Steel Tooth for medium formations 3 – Steel Tooth for hard formations 4 – Insert for soft formations 5 – Insert for soft/medium, formations 6 – Insert for medium/hard formations 7 – Insert for hard formations 8 – Insert for extremely hard formations Second digit – Designates the hardness subclass of major hardness class. This ranges from 1 to 4, where 1 is classified as the softest subclass and 4 is the hardest subclass.

Third digit – Designates the bit’s features: 1 – Roller bearing 2 – Roller bearing air-cooled 3 – Roller bearing with gage bevel inserts 4 – Sealed roller bearing 5 – Sealed roller bearing with gage bevel inserts 6 – Sealed friction bearing 7 – Sealed friction bearing with gage bevel inserts 8 – Directional 9 – Other Example:

IADC 6-3-2 This is a medium/hard air-cooled roller bearing.

Example:

12 1/4 MAGNT53CA 2 1/4 – Size MAGNT – Product Line 53 – First two digits of the IADC code (rock class “5” subclass “3”) C – Insert type (Conical inserts) A – Full armored lug

Insert/Tooth Type: • • • • • • • • • •

C – Conical N – Round Top O – Ogive S – Super Scoop F – Chisel 1 – Conventional Gage Tooth 2 – Tapered Gage Tooth 3 – “T” Gage Tooth 4 – “L” Gage Tooth 5 – “Web” Gage Tooth

Ovoids are standard inserts and do not have suffixes.

Lug Features: • • • • •

A – Armor B – Backreaming ST – Shirttail protection in tooth bits L – Streamlined lug R – Regular circulation

Other Features: • • • •


H – Hard Nose on cones G – Gage bevel on tooth bits T – Tough carbide (breakage resistant) W – Wear resistant carbide

159


Steel tooth bit selection Soft formation bits The Type S, regular circulation steel tooth bit is designed for optimum performance in formations of low compressive strength, such as soft sand rock, calcite, shale and clay. These formations quite often contain abrasive materials such as sharp sand and may be interspersed with layers of medium and hard formations. Soft formation bits are designed with long slim, strong teeth to permit deep penetration into the formation with comparatively light weight. Also, bit geometry is adjusted to give maximum desirable scraping action on bottom. So specific range of footage or penetration rates can be used as a yardstick for determining when to stop using this type bit, due to wide variation in weight, rotary speeds and formation variations encountered. However, if excessive tooth breakage occurs, you might safely assume that either the combination of weight and rotary speed is too great or formation is too hard for this type bit. Normally, these bits are run with relatively light weights, ranging from 1,000 pounds to 3,000 pounds per inch of bit diameter. Rotary speeds usually range from 120 to 170 revolutions per minute, depending upon the weight applied to the bit.

Medium formation bits The Type M and regular circulation steel tooth rack bits are designed for abrasive and non-abrasive medium formations. Note that this design differs from the “softer” types principally in the progressive strengthening of the teeth and change in bit geometry to provide more chipping-crushing action. These bits have more closely spaced teeth with a large included angle and more gage surface to resist the wear in harder and more abrasive formations. They are particularly efficient in formations where shales, sandy shales, and limestones alternate. Weight can be applied very effectively to these bits due to the more rugged construction of the cutting structure and bearings. However, excessive rotary speeds should be avoided to reduce the shock loads inherent in drilling these harder formations. This is especially important when formations are broken, causing rough operation. You should avoid combinations of weight and rotary speeds which promote rough running to prevent premature failure of bearings and cutting structure. Drilling weights commonly range from 1,000 to 5,000 pounds per inch of bit diameter, with rotary speeds from 60 to 100 revolutions per minute, depending upon the relative weight on the bit.

Hard formation bits Type H, regular circulation steel tooth rock bits are designed to drill hard formations which contain amounts of abrasive materials. Formations requiring the use of this bit type are those having: 1. High compressive strength with low abrasive content such as dolomite. 2. High compressive strength with high abrasive content such as dolomite and trap rock. 3. Medium compressive strength with high abrasive content such as quartz, sandstone and the copper ores. Compared with the soft and medium formation bits, this bit has higher capacity bearings and more closely spaced teeth with increased tooth angles to allow the use of heavier weights required to effectively drill hard formations. The geometry of this bit provides maximum chipping and crushing action with minimum scraping action. The outermost row of teeth on each cone is the driving row; that is, this row generates a rock gear pattern on bottom, which in the case of these strong rocks, is not easily broken up. Because of this, a webbed gage surface is generally used on heel rows of teeth to keep the patterns broken down. Tungsten carbide hardfacing is applied to the “webs” to strengthen the gage against abrasive wear. Type H bits are commonly run with weights ranging from 4,000 to 7,000 pounds per inch of bit diameter with rotary speeds decreasing from 40 to 80 revolutions per minute as weight is increased. Steel tooth Tricone rock bit type vs. rock hardness Rock UCS (PSI)

Steeltooth Tricone bit series

Rock Type

0

2,000

Unconsolidated Sands

S series

Limestone, Siltstone Clay Stone, Mudstone

4,000 Marl, Chalky Limestone

M series 6,000

Soft Shales 8,000 Consolidated Sandstones 10,000

H series Soft Marble, Dolomite

12,000 Tuff, Soft Schist 14,000 Rock UCS hardness (Unconfined Compressive Strength) is only one factor contributing to the “drillability” of any rock. Other factors influencing drillability are fracture toughness, shear strength, Young’s modulus of elasticity, Poisson’s ratio of stress vs. strain & internal angle of friction. Any particular bit may be used in harder or softer rock than this chart indicates.

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Steel tooth bits

Bit specifications

S Series The S series has widely spaced, long tapered teeth with broad, axial crests for the bottom-hole action necessary to achieve high penetration rates. Inter-fitted rows of teeth prevent formation packing and facilitate the cleaning action. The gage bevel is hardfaced for wear resistance. Tungsten carbide hardfacing on the other critical areas of the S series cutting structure provides superior abrasive wear resistance and allows the teeth to self-sharpen. Applications: Softer formations such as clays, shales, soft sandstones, and soft limestones. Suggested Operating Parameters: Weight on Bit – 1,000 to 3,000 lbs per square inch of diameter RPM – 70 to 120 IADC range 1-1-2 to 1-4-2

M Series M series bits are designed with shorter, stronger teeth to withstand the weight required for these formations. The M series shirttail is overlaid with tungsten carbide hardfacing for abrasive wear resistance. Applications: Medium formations, such as limestones, sandstones, and dolomites. Suggested Operating Parameters: Weight on Bit – 3,000 to 5,000 lbs per square inch of diameter RPM – 60 to 100 IADC range 2-1-2 to 2-4-2

H Series H series bits have a heavy gage bevel and short, closely spaced teeth to withstand heavier impact loads. Tungsten carbide hardfacing on the shirttail offers superior wear resistance. The H series has proven successful in drilling operations in which excessive gage wear must be avoided. Applications: Hard shale formations, limestones, sandstones, and dolomite formations. Suggested Operating Parameters: Weight on Bit – 4,000 to 7,000 lbs per square inch of diameter RPM – 60 to 80 IADC range 3-1-2 to 3-4-2


161


TCI bit selection Five basic classifications of Atlas Copco Secoroc rock bits are available for TCI (Tungsten Carbide Insert) blasthole drill bits. These are divided into the 40, 50, 60, 70 and 80 series rock bits. The principal design differences are in tailoring the cutting structure of each type to most efficiently drill specific formations. For example, 60 series bits are designed for drilling medium-hard to hard formations, the 70 series for hard formations and the 80 series for the hardest formations. The modifications in cutting structure design from series to series are: 1. The spacing of inserts or teeth is greatest for the softer or weaker formations and decreases as the formation hardness increases. 2. The number of rows and/or the total number of inserts or teeth per bit increases as formation hardness increases. 3. The groove depth and amount of intermesh is decreased as formation hardness increases. 4. The insert or tooth projection above the cone shell is greatest for the softer formations and is decreased as the formation hardness increases.

Bit specifications 50 series

The 50 series bits are typically characterized by more densely spaced chisel or conical inserts. This configuration promotes maximum penetration rates in soft/medium formations that are fractured or have varying degrees of hardness. Applications: Soft/medium formations such as sandstone, shale, granite and some marble. Suggested operating parameters: Weight on bit - 3,000 to 6,500 lbs/inch of diameter Rotations speed - 50 to 150 RPM

Specifications 40 series

60 series

Applications: Soft formations such as shale, siltstone, soft limestone and alluvials.

Applications: Medium/hard formations such as hard limestone, hard shale, basalt and quartzite.

The 40 series bits are typically characterized by large diameter widely spaced super scoop, chisel or conical inserts. The configuration promotes maximum penetration rates in softer formations that have a tendency to stick and ball up the cutting structure.

Suggested operating parameters: Weight on bit - 1,000 to 5,000 lbs/inch of diameter Rotation speed - 50 to 150 RPM

162

The 60 series bits are typically characterized by more densely spaced, shorter projecting chisel, concial or ogive inserts. This configuration promotes maximum penetration rates in medium/hard formations.

Suggested operating parameters: Weight on bit - 4,000 to 7,000 lbs/inch of diameter Rotation Speed - 50 to 120 RPM



TCI (Tungsten Carbide Insert) bits 70 series

Bit specifications

80 series

The 70 series bits are typically characterized by densely spaced, shorter projecting conical or ogive inserts with a conical or ovoid/ round top gage insert. This configuration promotes maximum penetration rates in hard formations.

The 80 series bits are typically characterized by very densely spaced, short projecting ovoid/round top inserts. This configuration promotes maximum penetration rates in extremely hard formations. Applications: Extremely hard formations such as chert, hematite ore and quartzite.

Applications: Hard formations such as taconite, banded iron and quartzite. Suggested operating parameters: Weight on bit - 4,000 to 8,000 lbs/inch of diameter Rotation speed - 50 to 90 RPM

Suggested operating parameters: Weight on bit - 6,000 to 9,000 lbs/inch of diameter Rotation speed - 40 to 80 RPM

Technical Data Pin connection sizes and make-up torques Bit size range

Connection size

Torque range kilogram force meter

pound force foot

277-346

2,000-2,500

2 3/8

415-484

3,000-3,500

73

2 7/8

622-760

4,500-5,500

89

3 1/2

970-1240

7,000-9,000

mm

inch

mm

73

2 7/8

95-114

3 3/4-4 1/2

60

117-137

4 5/8-5 3/8

143-171

5 5/8-6 3/4

inch

N-Rod* N-Rod*

194-229

7 5/8-9

114

4 1/2

1660-2210

12,000-16,000

251-349

9 7/8-13 3/4

168

6 5/8

3870-4420

28,000-32,000

381-445

15-17 1/2

194

7 5/8

4700-5530

38,000-40,000

*Non-standard API


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TCI (Tungsten Carbide Insert) bits

Bit selection

Tricone carbide insert rock bit series vs. rock hardness Rock UCS (psi) 0 4,000

Tungsten carbide insert Tricone bit series

Rock type Claystone, Mudstone

40 series 4-1 to 4-4

Chalky Limestone Soft Shale Loose Sandstones

8,000

Limestone, Siltstone Solid Sandstones

12,000 16,000

Medium Shales

MAG NT series


Tuff, Soft Schist Andesite, Rhyolite Quartzite (Sand, Silt)

20,000

Limestone, Marble Monzonite, Granite

24,000

Gneiss

Epsilon series

28,000 32,000

Diorite, Diabase Hard Shale, Slate


Limestone, Dolomite Basalt Tactite, Skarn

36,000

Granodiorite HD NT series

40,000

Taconite Quartzite Syenite

44,000 48,000


Gabbro Banded Iron Formation Taconite

52,000

Chert

56,000

Quartzite

60,000 64,000


Amphibolite Hornfels

68,000

Hematite Ore

Higher

“Lava”, Basalt, Biwabic, Quartzite

Rock UCS hardness (Unconfined Compressive Strength) is only one factor that contributes to the “drillability” of any rock. Other factors strongly influencing drillability are: fracture toughness, shear strength, Young’s modulus of elasticity, Poisson’s ratio of stress vs. strain, internal angle of friction. Any particular bit may be used in harder or softer rock than this chart indicates.

164



When to change a bit At most mines the decision when to change the bit is typically left up to the driller, with very little guidance given. This results in most bits being changed only after they have been completely worn out. We believe that a typical operation can save $000’s annually by applying some simple rules.

Tricone bits Analyzing a typical bit run Rig cost: $200 Bit cost: $3,550

At the end of a Tricone bits life the cutting structure becomes ineffective either through breakage or wear, resulting in reduced penetration rate. Using the TDC formula, “cost effective” bit life can be calculated and related to penetration rate, giving the drill operator a guide as to when to change the bit.

This bit has too many broken teeth to be effective any longer.

Date

Meters

Hours

ROP

TDC/m

9-Oct

727

9

80.8

$7.36

10-Oct

1,597

20

80.7

$4.70

11-Oct

2,308

29

80.2

$4.03

12-Oct

3,106

38

81.6

$3.59

13-Oct

3,573

46

77.6

$3.57

14-Oct

4,078

54

76.1

$3.50

15-Oct

4,431

58

76.5

$3.42

16-Oct

4,753

62

76.7

$3.35

17-Oct

5,251

70

75.0

$3.34

18-Oct

5,662

76

74.7

$3.31

19-Oct

6,174

83

74.5

$3.26

20-Oct

6,774

91

74.6

$3.21

21-Oct

7,162

99

72.7

$3.25

22-Oct

7,459

107

69.9

$3.33

23-Oct

7,893

117

67.4

$3.41

24-Oct

8,295

127

65.2

$3.51

Analyzing a typical bit run, as shown in the table above, the optimum point in time to pull a bit can be identified. It is seen that had the bit been removed on the 20th of October, the run would have been $0.30 per meter more cost effective than on the 24th October. Based on 250,000 meters drilled annually, the projected savings would be $75,000 per annum.

TDC Penetration Rate

$7.00

- 80.0

- 75.0

$6.00 $5.00

- 70.0

$4.00 $3.00 Optimum time to change bit. Lowest TDC = $3.21 per meter

$2.00

- 65.0

$1.00 - 60.0


8295

7492

7893

7162

6174

6774

5662

5251

4753

4431

4078

3106

3573

2308

727

Worn teeth cannot penetrate the rock, therefore productivity diminishes.

1597

$

Meters Drilled

165

Penetration rate (m/hr)

$8.00


How a rock bit drills

Rock failure

Rock cutting, abrasion - vergy small cracks, insert grinds surface.

Rock cutting, spalling starts - enough weight applied to hard rock deeper. Cracks connect. Chips will come free with air blast.

Abrasion

Spalling

This is an illustration of the first phase of rock failure, called the abrasion phase. This is the result of insufficient weight on the bit. The inserts are contacting the rock under very low weight and the resulting action is very similar to placing a knife blade against a grinding stone. The driller can very easily tell when he is in the abrasion phase because the cuttings coming out of the hole will be fine dust.

Here, rotation speed (RPM) is still the same but sufficient weight has been applied to the bit for most effective insert penetration into the formation. Note that the shell of the bit is not against the formation.

Rock cutting, deeper abrasion - deeper cracking, but does not connect. Next cone must crack rock between these teeth. Rock cutting, deep spalling - cracks connecting at deeper levels. Cracks connect bertween teeth and between rows.

Fatigue

Here, more weight has been added to the bit with RPM the same as in the previous illustration. The additional weight has caused some penetration of the inserts into the formation, but not actual failure of the rock. This is called the fatigue phase and again, the driller can easily recognize this phase by checking the returns. Small chips and a high percentage of dust will be coming out of the hole.

In thix second illustration, the inserts are loaded under the proper weight to cause the formation to spall. Chips are removed by the circulating air, allowing the cutting structure to advance. Under “load” condition, the bit will drill at maximum efficiency. The driller will note a large amount of chips with very little dust or fines in the returns.

It should be pointed out that rock failure can be accomplished with this type of loading and insert penetration. However, it may require many impacts on the formation to cause the rock to fail. The penetration rate will be considerably less than desired.

166



How a rock bit drills

Cutting efficiency RPM vs ROP

ROP

RPM

Rock cutting, overpenetration - cuttings trapped betwween cone shell and rock. Cannot be blown out by air blast from nozzles.

Excess weight

Once the spalling phase has been achieved, applying additional weight to the bit will only be harmful to drilling efficiency. The additional weight will cause the inserts to bury themselves in the formation. The result is a decrease in penetration rate.

Maximize ROP

With the bit drilling in the spalling phase, it is possible to increase the penetration rate by maintaining the proper weight, while increasing the rotation speed (RPM). The amount of increase possible in the penetration rate is variable and will be determined by the experience of the driller, the capabilities of the drill and the formation characteristics.

Maximum Drilling Efficiency

WOB vs ROP

RPM ROP

ROP

Weight on Bit (Pulldown)

Maximum cut efficiency

With rotation speed (RPM) fixed, this illustration shows the effect of weight increases on the rate of penetration. After the formation has been “spalled” additional weight will reduce or not increase the drilling rate.

Weight on Bit

Maximum drilling efficiency

The preceding charts illustrate: spalling weight plus rotation speed equals penetration rate. Therefore, optimum drilling efficiency may be reached as follows: At a set RPM, determine best weight on bit (WOB) to produce maximum cut efficiency. At the WOB that gives maximum cut efficiency, RPM should be determined to produce best rate of penetration. Note: High rotary speeds do not necessarily produce high penetration rates.


167


Importance of records

Tricone bits

Drilling hours

Bit selection

Keeping complete and accurate records of blast hole bit performance cannot be stressed too much. A careful study of bit records can be of considerable help in determining the proper bit types and best operating conditions to use. The meters drilled by a bit and the penetration rate have long been accepted “yardsticks” for evaluating the performance of a rock bit. However, these are two different units of measure and many erroneous conclusions have been drawn from these two factors alone. It is therefore necessary to combine these two units of measure into one, known as Total Drill Cost per meter or TDC/meter.

A careful study of bit performance records can be of great help in deducing operation costs through selection of the most economical bit types and operating conditions. An actual case in which the performance records and bit selection were given full attention is illustrated in the following example:

Summary of average performance data Bit type Bit cost

Standard product

Premium product

US $2500

US $2875

The Total Drilling Cost is then, the cost of the bit plus the cost of operating the drill.

Meters/bit

5400

5000

Meters/hour

28

32

The simplistic cost/m would use bit cost/meters drilled, indeed this makes up one half of the TDC/m equation. The speed at which the bit drills is included by dividing the cost of the drill/hour by the penetration rate of the bit.

Rig cost/hour

120

120

25000 kg

25000 kg

80-100

80-100

4.75

4.33

Hence: TDC $/m = Bit cost Bit meters

+ Rig cost/hour

Bit drilling speed

It may be seen in the Table below that three bits of type A were run alternatively with three bits of type B. The record indicates that the formation drilled was relatively uniform. Type A average 1418 meters in 27.8 hours; type B averaged 1577 meters in 33 hours. Which bit was most economic if bit costs were the same at US $3000 and rig rate per hour was US $120/hour?

Weight RPM TDC/meter

Analysis of the standard product, indicated that gage row cutting structure was worn, leading to shirttail wear and failure. The premium product, with enhanced tungsten carbide insert features to allow maximum penetration rate was tried. Using the TDC $/m equation introduced earlier and performance data from above, a breakeven graph can be constructed.

Type A bit TDC $/m = $4.47 Type B bit TDC $/m = $4.57 Now the bits can be compared and Type A is the better bit with the lower TDC$/m.

Typical bit performance record Bit type

Meters Hours Rate Weight Rotary drilled run M/hr in Kg RPM

Premium product Soft Med. Hard

A

1907

38.1

50.1

40000

70/90

X

B

1913

39.5

48.4

40000

70/90

X

A

1303

23.9

54.5

40000

70/90

X

B

1485

32.3

46.0

40000

70/90

X

A

1044

21.3

49.0

40000

70/90

X

B

1334

27.3

48.9

40000

70/90

X

Avg. A

1418

27.8

51.1

Avg. B

1577

33.0

47.7

168



Importance of records

Tricone bits

Drilling hours premium bit breakeven performance

5500 5000 Breakeven Costs

Meters drilled

4500 4000 3500

156 hours

3000 2500 3000

Step 1

Premium bit cost Rig cost/hour

= Hours (point A)

2875 120

= 24

*Plot to the left of zero on the X axis

1500 1000

605 m step 2 (point B)

500 -25

25

50 75

100

125

150

175

-24 step 1 (point A)

Step 2

Premium bit cost = Meters (point B) Standard TDC $/m

2875 4.75

= 605

Hours

Step 3

Draw a straight line through points A and B

Bit performance above the line will return a profit for the additional investment in the premium product.

Rotary Tricone Blasthole Drilling Rock Type

All rock types, all rock strengths

Hole Sizes

5 5/8" - 17 1/2" (143 mm - 445 mm)

Hole Depth

10 ft - 250 ft (3.04 M - 76.2 M)

Rate of Penetration, Hole-to-hole

Soft (coal overburden): 100 - 300 M/hr

Hard (iron ore): 20 - 60 M/hr

Straightness of holes

Very good in typical 10 - 20 meter “benching” operations

Suggest using drill string roller stabilizer in long holes for casting or “deep benching” operations

Production Capacity, Typical Tons/ Shift per drill (10 hrs.)

Coal overburden, 7 7/8" (200 mm) bit: 75,000 tons

Iron Ore, 12 1/4" (311 mm) bit: 30,000 tons

Low Fuel Consumption, Ltr/Hr

75 - 90 l/hr small to medium drill (0.01 - 0.012 ltr/t)

100 - 120 ltr/hr medium to large drill (0.03 - 0.04 ltr/t)

Economic Drill String Life, M

300,000 meters/pipe, non abrasive rock

40,000 meters/pipe, highly abrasive pipe

Low Drill String Investment

Yes, relative to size and hole depth

Suitable for Difficult Drilling Conditions

Yes

Suitable for Good Drilling Conditions

Yes

Operator Friendly

Yes, larger drill cabs, more room, more available amenities

Flushing Flexibility

1000 to 4000 CFM, (28.3 - 113.3 cuM/min) depending on drill and bit size. Able to adjust bit air pressure with different nozzles. Compatible with “high pressure” (350 psi/24 bar and higher) air compressors.


169


Air practices Air is a critical factor in tricone rotary blasthole drilling performance. Without proper air flow, tricone rotary blasthole bits cannot be operated efficiently. Bit bearings are not kept clean and cool. Cuttings are not blown away from the cutting face of the bit and moved up and out of the hole. The operating cost of drilling a hole increases.

Key Concepts Standard Air

Air is a compressible gas. In air compressor design, air compressor work and air flow calculations, the standard unit of volume is the cubic foot. The standard temperature is 70 degrees Fahrenheit, and the standard elevation is 0 feet, or sea level. Standard atmospheric pressure at sea level is 14.7 psia. The Standard Cubic Foot (SCF) of air has a standard mass of 0.07494 pounds. (Standard density is .07494 lb./cu. ft.) All engineering air flow calculations are based on the Standard Cubic Foot and standard conditions: standard air mass, standard air temperature, and standard atmospheric pressure.

Introduction Whenever ‘standard’ air volumes are calculated, sea level atmospheric pressure, 14.7 psia, must be added to gauge pressure.

Gas Law Physics

Boyle’s Law states that at a constant temperature, the volume of a gas varies inversely with the absolute pressure: P1 x V1 = P2 x V2 Charles’ Law states that at a constant pressure, the volume varies directly with the absolute temperature: V1 x T2 = V2 x T1 Amonton’s Law says that at a constant volume, the absolute pressure varies directly with the absolute temperature: P1 x T2 = P2 x T1 In our work, Boyles’, Charles’, and Amontons’ laws all interact through the Combined Gas Law equation: P1 x V1 = P2 x V2 T1 T2

Air Density and Atmospheric Pressure

Actual Air “Actual” air is the “free” air outside of the drill bit that does the work in drilling. Compressed air does not move cuttings away from the cutting face of the bit. Compressed air does not move rock particles up the blasthole from the bit to the surface. Compressed air must be released to “atmospheric” or “ambient” or “actual” site specific conditions before any work can be done. “Actual” air is derived from “standard” air by applying the Altitude/Temperature factor:

Absolute vs. Gauge Pressure

Pressures are variously reported as “psia” and “psig”. The ending letter, “a” or “g”, refers to whether the pressure being discussed is “absolute” pressure or “gauge” pressure. “Absolute pressure” is the sum of the local ambient atmospheric pressure plus any pressure reading on a pressure gauge. “Gauge pressure” is the pressure indicated by a pressure gauge in the air system.

As altitude increases, the ambient (local) atmospheric pressure decreases. The column of air above that particular point on the earth’s surface is not as deep, therefore it weighs less, and exerts less pressure on that point. This allows the “contents” of a SCF to expand until equilibrium with the new atmospheric pressure is reached. What starts out as one (1.00) standard cubic foot of air becomes larger, because the atmospheric pressure confining it is less. At sea level, atmospheric pressure is 14.7 psia. At 5000 feet, atmospheric pressure drops to 12.23 psia. This allows the same weight of air, .07494 lb. (contained in one cubic foot) to expand into a larger volume. Because it now has a larger volume, the density is less. At 5000 feet, and 70 Deg. F, one (1) ambient cubic foot of air weighs .0623 pounds. The original SCF, weighing .07494 pounds has expanded into 1.202 cubic feet: .07494 lb / .0623 lb = 1.202. Temperature has the same effect on air as does confining pressure (altitude). As temperature increases, the density of air decreases. This can be seen from the gas laws. Conversely, as altitude decreases, air becomes more dense. 1.000 SCF becomes 0.89 SCF at -2,000 feet, and has a density of .0834 pounds per cubic foot.

At sea level and 70o F, a Cab gauge pressure of 37 psig is therefore equivalent to 51.7 psia: 37 psig + 14.7 psi ambient atmospheric pressure = 51.7 psia. At 5000 feet, and 70o F the same cab gauge reading would be equivalent to 49.23 psia: 37 psig + 12.23 psia (atmospheric pressure at 5,000 ft, 70o F) = 49.23 psia. If no “a” or “g” appears after psi, the pressure is taken to mean gauge pressure.

170



Air practices Altitude/Temperature Factor The A/T factor is used to adjust (“derate”) air compressor intake ratings in response to changes in local altitude and ambient temperature; and to “expand” the calculated compressed air output to local conditions. The A/T factor also helps to calculate the % Capacity of the air compressor during an air compressor volume test; and using the measured delivered SCFM (which may be quite different from the specification volume rating) calculates the Bailing Velocity, Chip Settling Velocity, and the Chip Exit Velocity. For example, the A/T factor for 5,000 feet and 70o F is 1.202. (14.7 psia standard atmospheric pressure at 0 feet /12.23 psia ambient atmospheric pressure at 5,000 feet = 1.202.)

Bailing Velocity

The speed of the actual air moving up a blasthole. A geometrical calculation dependent on bit diameter, drill pipe diameter, and the volume of air circulated through the hole. Bailing Velocity must be higher than Chip Settling Velocity or cuttings will not be transported.

Chip Settling Velocity The velocity a rock chip falling through air wants to achieve. Theoretical values are calculated from an adaptation of Stokes Law. Dependent on cuttings diameter and rock specific gravity.

Chip Exit Velocity The speed the cuttings (chips) move up the hole. The difference between Bailing Velocity and Chip Settling Velocity: CEV = BV - SV.

Tricone rotary blasthole drill air requirements There are two things that clean cuttings from a rotary blasthole and must be combined to make drilling efficient: air pressure and air volume. Air pressure determines the force of the jet nozzle air blast blowing against the bottom of the hole to move cuttings away from the face of the bit.

Air requirements Two other factors that affect the air requirements are the moisture content of the rock and cuttings, and the incidence of fractures and joints. Wet rock, due to ground water or excessive water injection, will be heavier than the same rock when dry. Cuttings from wet rock tend to stick together, making larger particles to be blown from the hole. Fractured or jointed ground will rob air from the blasthole, causing the actual bailing velocity to be lower than the calculated bailing velocity. In both of these instances, the actual air volume required may be much higher than what straight theoretical calculations indicate. Experience is the best guide.

Recommendations: Bailing Velocity

Bailing Velocity is dependent on three things: ACFM (free air), hole diameter, and drill pipe outside diameter. The value normally calculated is a geometric and theoretical value that assumes a perfectly drilled straight hole with no air losses out the side of the holes through cracks and fractures. We must assume this because no one ever measures a blasthole specifically for its diameter. Under normal conditions of dry rock, very light water injection, little or no ground water, and few if any joints or fractures, minimum bailing velocities of 5,000 to 7,000 feet per minute (FPM) can be used. In situations where the rock is a denser, heavier material, velocities up to 9,000 FPM could be used with little problem. In situations where the rock is wet, or dense, or there is a high penetration rate (above 180 feet per hour), bailing velocities of 9,000 FPM or more may be needed. Again, it will depend on individual situations. The overriding recommendation for bailing air is to have a minimum of 1,000 feet per minute Chip Exit Velocity with drill pipe worn to replacement diameter. If this condition is met, bailing performance will be good under all other conditions. Annular pressure calculations will not be discussed here. Once the reader understands the ‘basics’ of compressed air use in blasthole drilling, they should pursue an advanced knowledge of rotary blasthole annular pressures by obtaining those materials from Secoroc in Grand Prairie, Texas, USA. The following discussion of Particle Settling Velocity is intended to illustrate the problems of varying rock densities and chip sizes, and how they affect the rate of chip removal from the drill hole.

Air volume, as bailing velocity, lifts cuttings up out of the hole once they are moved away from the bit face.


171


Air practices

Particle settling velocity

Particle Slip (or Settling) Velocity

Cuttings particles fall through air at velocities dependent on particle density, particle diameter and shape, and air density. Large, heavy particles fall faster than small, light ones. “Slip velocity” is the speed at which a particle falls through still air. It is also called settling velocity. Slip velocities in air may be much higher than one would expect. If the bailing velocity in a hole is not greater than the slip velocity of a given size particle, that particle will not be carried from the hole. It will be reground until it is of a small enough size to be carried out by the air stream. Remember: bigger chips indicate more efficient drilling, and yield faster penetration rates. The following particle slip velocity equation is from Walker and Mays, Journal of Petroleum Technology, July 1975.

Particle Slip Velocity Vt = {(2G x dp x (DenP - DenF)) / (1.12 x DenF)}.5

Where:

Vt = Terminal Slip Velocity of particle, ft / sec G = Gravity, 32 ft / sec2 dp = Diameter of Particle, feet DenP = Density of Particle, lb / cubic foot DenF = Density of Fluid, lb / cubic foot

Sufficient air pressure at the bit must be present to insure that plenty of air is going through the bit bearings. Bearing air is necessary to: 1) keep the bearings cool, and 2) keep the bearings clean. Hot and/or dirty bearings will cause early bit failure. With air pressure systems whose minimum operating pressure is greater than 35 psig, Atlas Copco Secoroc generally recommends bit pressures of 40 psig to 45 psig minimum. This range has been found to provide enough pressure in the bearings to keep them clean and cool, and still direct plenty of air through the nozzles for good bottom hole cleaning. The Atlas Copco Drilling Solutions blasthole drill air compressor is normally capable of generating 110 psig at the receiver tank. Because of the higher level of air pressure available on these drills for tricone drilling, Secoroc suggests that tricone bit pressures can be in the 60 - 65 psi range without causing any problems. Full volume will be delivered as long as the air compressors are properly adjusted, and operating to their specified parameters.

Nozzle Selection Bearing Life

Given: Chip diameter = .125”, .25”, .50” DenP =

145 lb / ft3 for Sandstone 168 lb / ft3 for Granite 181 lb / ft3 for Dolomite

DenF =

.07651 lb / ft3 for air at sea level and 59o F

Terminal Settling Velocity, feet / minute: Also take into consideration that as altitude increases, air density decreases; thus, particle slip velocity will increase. Moving from sea level to 5,000 feet, air density drops to .0637 lb/cu ft. The settling velocity of a 1/2 inch chip of granite increases from 4330 ft to 4755 ft. It can now be seen that chips do not leave the hole at the calculated bailing velocity, and that loss of air from any part of the hole can reduce the actual bailing velocity to below the settling velocity of the chips the bit actually generates. Recommended bailing velocities of 5,000 FPM are a minimum recommendation!

Chip Diameter

Sandstone

Granite

Dolomite

1/8”

2013

2166

2249

1/4”

2847

3064

3181

1/2”

4031

4339

4503

172

Bit Pressure Drop

Bearing life can be increased by using smaller nozzles in the bit. With smaller nozzles, proportionally more air is forced through the bearing system, providing more cleaning and cooling. Dulling characteristics of bits should be determined. If shirttail erosion and exposure or loss of outer bearings is common, increased air through the bearings will probably help bearing life by keeping the cone backface and shirttail lip cleaner. If bit failure is not due to an erosive bearing failure (such as described above), and the cutting structure is not highly damaged or eroded, smaller nozzles could again help by forcing more air through the bearings. In this instance, however, it is the cooling of the bearings that is being enhanced. As the bearings rotate under load, heat is generated. Too much heat build up causes thermal degradation of the bearing metal. The air in the bearings still retains some of the heat gained during compression, and may not provide enough cooling capacity at low pressures (and flow rates) for the bearings. At higher pressures, the cooling capacity of the air is increased due to the increased volume passing through the bearings, so the bearings stay cooler, prolonging their life.

Bottom Hole Cleaning

Bottom hole cleaning is a function of the “force” or “power” the air blast exerts on the bottom of the hole. Two things must happen. First, there must be enough power exerted on the cuttings to dislodge them from their position on the hole bottom. Cuttings may be Blasthole Drilling in Open Pit Mining


Air practices

Force exerted by air

laying loose on the bottom, or they might be partially or completely trapped under a layer of crushed material. Second, the cuttings must be transported out from under the bit. The first situation, freeing the cuttings, requires more “power” than transporting the cuttings. Once cuttings are loose, they are relatively easily transported. In the “Force Exerted By Air Calculation” to the right, the force of air leaving a bit nozzle is calculated. Pressures and temperatures are actual parameters found on a drill equipped with a two-stage compressor. Air volume is converted to weight. Air velocity at nozzle exit is calculated. Multiplying the air discharge in “pounds per second” by the air velocity in “feet per second” gives the quantity “pound feet/sec2” This converts to a measure of force, kg meter / sec2, the “Newton”.The calculations are all at “Standard Conditions”. In the “Force Exerted by Air Calculation”, it can be seen that smaller nozzles will apply more force to the hole bottom for cleaning. The added benefit is increased air through the bearings, keeping them cleaner and cooler.

the variations of the coefficient of flow for the orifices. The above flows were calculated with a .80 coefficient of flow. If the coefficient was .78 for 1/2” and .82 for 5/8”, the flows would be virtually identical. The actual air test was done with 7/8”, 1”, and 1 1/8” orifices. With a coefficient of .78, calculated dSCFM’s for the orifices were 796.9, 796.5, and 797.2 SCFM respectively. No real change from small to large. Caution is advised. Although the volumes changed very little, the amount of force increases with velocity. The increased scouring action, if carried to an extreme, could result in increased erosion of the bit. The increased blast will carry cuttings at a higher velocity, possibly to the detriment of the bit. This can be especially true if penetration rates are high and cuttings are abrasive. Keep in mind that 30% to 50% of the air in a bit goes through the bearings, and is not used to clean the bottom of the hole. Only with adequate pressure in the bit can you move cuttings out before they can be reground. Increased force on the bottom of the hole will give better cleaning. Better cleaning equals higher ROP. Higher ROP equals a lower Total Drilling Cost.

Force Exerted by Air Calculation Given 1/2”

9/16”

5/8”

Nozzle Diameter

79 psig

57 psig

42 psig

Tool Air Pressure

117º F

117º F

117º F

Tool Air Temperature

260 CFM

252 CFM

246 CFM

dSCFM

Calc./Nozzle (CFM) / 60) x .07494 = lb per second CFM / 60 / Nozzle area (sq. ft.) = Air velocity, ft/sec lb/sec x ft/sec = lbft/sec2 Calculate 1/2”

9/16”

5/8”

.3250 lb/sec

.3157 lb/sec

.3072 lb/sec

3089.5 ft

2470.5 ft

1952.6 ft

138 N

107 N

82 N

Nozzle Diameter Air Weight Delivered Air Velocity Newton’s Force/ Nozzle

1 lb ft / sec2 = .1382 kg meter / sec2 1 kg meter / sec2 = 1 Newton

Something is seen in this calculation that runs contrary to popular wisdom. As nozzle size increased, the volume and weight of air delivered decreased. This can be attributed to inaccuracies in air temperature, air pressure, and Blasthole Drilling in Open Pit Mining

173


Air practices

Suggested nozzle sizes

Suggested Nozzle ID Sizes for Secoroc Tricone Rotary Blasthole Bits Nozzle ID Calculations use the following as constants: • Suggested Bit Pressure of 65 psi for Atlas Copco Drills only (pressure at Cab Gauge will be higher). • 110 °F delivered bit air temperature • 70 °F air compressor intake temperature Enter Altitude of Drill Site in Feet: 1000 Meters x 3.28 = Feet

A/T Factor: 1.057

Air Compressor Intake Rating - CFM Bit Diameter inches

mm’s

750 inches

900 mm’s

inches

1050 mm’s

inches

1200

mm’s

1400

inches

mm’s

inches

1900

mm’s

2600

inches

mm’s

3800

inches

mm’s

inches

mm’s

5 5/8

143

1/2

12

1/2

13

9/16

14

5/8

16

11/16

17

3/4

20

15/16

23

1 1/8

28

5 7/8

149

7/16

12

1/2

13

9/16

14

5/8

15

11/16

17

3/4

20

15/16

23

1 1/8

28

6

152

7/16

12

1/2

13

9/16

14

5/8

15

5/8

17

3/4

20

15/16

23

1 1/8

28

6 1/4

159

7/16

12

1/2

13

9/16

14

5/8

15

5/8

17

3/4

20

15/16

23

1 1/8

28

6 3/4

171

7/16

11

1/2

13

9/16

14

9/16

15

5/8

16

3/4

19

15/16

23

1 1/8

28

7 3/8

187

7/16

11

1/2

13

9/16

14

9/16

15

5/8

16

3/4

19

7/8

23

1 1/8

28

7 7/8

200

7/16

11

1/2

12

1/2

13

9/16

14

5/8

16

3/4

19

7/8

23

1 1/16

28

8 1/2

216

3/8

9

7/16

10

1/2

12

1/2

13

9/16

15

11/16

18

7/8

22

1 1/16

27

9

229

3/8

9

7/16

10

1/2

12

1/2

13

9/16

15

11/16

18

7/8

22

1 1/16

27

9 7/8

251

1/4

6

5/16

9

3/8

10

7/16

12

1/2

13

11/16

17

13/16

21

1 1/16

26

10 5/8

270

1/8

4

1/4

7

3/8

9

7/16

10

1/2

12

5/8

16

13/16

20

1

26

290 mm

290

X

X

1/4

6

5/16

8

3/8

10

7/16

12

5/8

16

13/16

20

1

26

11

279

X

X

1/4

6

5/16

8

3/8

10

7/16

12

5/8

16

13/16

20

1

26

12 1/4

311

X

X

1/4

6

5/16

8

3/8

10

7/16

12

5/8

16

13/16

20

1

26

13 3/4

349

X

X

X

X

3/16

6

5/16

8

3/8

10

9/16

15

3/4

19

1

25

15

381

X

X

X

X

3/16

4

1/4

7

3/8

10

9/16

14

3/4

19

1

25

16

406

X

X

X

X

X

X

3/16

5

5/16

8

1/2

13

11/16

18

15/16

24

17 1/2

445

X

X

X

X

X

X

X

X

3/16

5

7/16

12

11/16

17

15/16

23

CO P O ly C AS s On L AT ill Dr

174



Air practices (other brand drills)

Suggested nozzle sizes

Suggested Nozzle ID Sizes for Secoroc Tricone Rotary Blasthole Bits Nozzle ID Calculations use the following as constants: • Suggested Bit Pressure of 45 psi for other brand drills only (pressure at Cab Gauge will be higher). • 110 °F delivered bit air temperature • 70 °F air compressor intake temperature Enter Altitude of Drill Site in Feet: 1000 Meters x 3.28 = Feet

A/T Factor: 1.019

Air Compressor Intake Rating - CFM Bit Diameter

900 inches

1200 mm’s

inches

1600

inches

mm’s

mm’s

inches

5 5/8

143

X

X

X

X

X

5 7/8

149

5/8

16

3/4

18

13/16

2000

mm’s

2500

inches

mm’s

inches

X

X

X

21

X

X

3000

3600

3800

mm’s

inches

mm’s

inches

mm’s

inches

mm’s

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

6

152

5/8

16

3/4

18

13/16

21

X

X

X

X

X

X

X

X

X

X

6 1/4

159

5/8

16

11/16

18

13/16

21

X

X

X

X

X

X

X

X

X

X

6 3/4

171

5/8

15

11/16

18

13/16

21

X

X

X

X

X

X

X

X

X

X

7 3/8

187

5/8

15

11/16

18

13/16

21

X

X

X

X

X

X

X

X

X

X

7 7/8

200

9/16

15

11/16

18

13/16

21

X

X

X

X

X

X

X

X

X

X

8 1/2

216

9/16

14

5/8

17

3/4

20

X

X

X

X

X

X

X

X

X

X

9

229

9/16

14

5/8

17

3/4

20

7/8

23

1

26

X

X

X

X

X

X

9 7/8

251

1/2

12

5/8

15

3/4

19

7/8

22

1

25

X

X

X

X

X

X

10 5/8

270

7/16

11

9/16

14

11/16

18

13/16

21

15/16

24

X

X

X

X

X

X

290 mm

290

7/16

10

9/16

14

11/16

18

13/16

21

15/16

24

X

X

X

X

X

X

11

279

7/16

10

9/16

14

11/16

18

13/16

21

15/16

24

X

X

X

X

X

X

12 1/4

311

7/16

10

9/16

14

11/16

18

13/16

21

15/16

24

1 1/16

27

1 3/16

30

1

31

13 3/4

349

5/16

9

1/2

13

11/16

17

13/16

20

15/16

23

1 1/16

26

1 3/16

30

1

31

15

381

5/16

8

1/2

12

5/8

16

3/4

20

15/16

23

1

26

1 1/4

29

1

30

16

406

1/4

6

7/16

11

5/8

16

3/4

19

7/8

23

1

26

1 1/4

29

15/16

30

17 1/2

445

1/4

6

3/8

9

9/16

14

11/16

18

7/8

22

1

25

1

28

15/16

29

nd a br nly er s O h Ot rill D


175


Air requirements and nozzle selection In rotary blasthole drilling, there is always a concern with delivery of air in sufficient volume and at the proper pressure to assure optimum bit performance when drilling with recommended bit weight and RPM. Sufficient air volume should be provided to produce an annular return velocity of 5,000-7,000 ft./min. for light, dry materials; and 7,000-9,000 ft./min. for materials that are wet and/or heavy, and when drilling at penetration rates of 35 m per hour or higher. To determine volumetric requirements, the simple Flow equation Q = AV may be used. Since friction losses in the annulus of relatively shallow holes of blasthole drilling are negligible, this becomes: Q=

V 183.35

Air Volume requirements for various hole diameter and drill pipe combinations - for 5,000 ft. and 7,000 ft. per min. annular velocity D. hole diameter (in)

D. pipe O.D. (in)

Q. - 5,000 CuFt/ min free air

Q. - 7,000 CuFt/ min free air

2 7/8

327

458

4 1/2

3 1/2

218

305

4

116

162

2 7/8

390

546

3 1/2

282

395

4

178

249

2 7/8

491

687

3 1/2 4

382 280

535 392

2 7/8

637

892

3 /12

530

742

4

426

596 1,025

4 3/4

5 1/8

5 5/8

(D2 - d2) 6 1/4

The table on this page shows volumetric requirements in cubic feet of free air per minute necessary to provide both 5,000 and 7,000 ft. per min. annular velocity for various possible combinations of hole size and drill pipe size.

6 3/4

The equation used is the simple flow equation: Q = AV. 7 3/8

With all constants combined and area expressed as difference between hole and pipe areas, this equation becomes: Q = 27.27 (D2- d2). • Q = cubic feet per minute free air necessary to obtain 5,000 feet per minutes annular velocity

7 7/8

• d = drill pipe outside diameter, inches • D = hole diameter, inches

9

Should Q be desired for some annular return velocity “V” other than 5,000 feet per minute, the result obtained above or from the table should be multiplied by the factor: V/5000.

9 7/8

Example: A 9 7/8” hole being drilled with 7 3/4” drill pipe at a desired annular velocity of 5,000 ft. per minute. Solution: Q = 27.27 [(9 7/8)2 - (7 3/4)2] = 27.27 [97.52 - 60.06] = 1022 cu. ft. per min. (shown in table) Had 7,000 ft. per min. velocity been desired: Q = (1022)

V7000 5000

= 1431 cu. ft. per min.

The above equation may also be rewritten to solve for annular velocity “V” when available compressor capacity, hole size and pipe size are known. V (ft./min.) =

176

183.35Q (D2 - d2)

Tricone bits

11

12 1/4

13 3/4

15

17 1/2

3 1/2

732

4 1/2

513

718

5

382

535

3 1/2

908

1,271

4

805

1,127

4 1/2

690

966

5

560

784

3 1/2

1358

1,900

4 1/2

932

1,305

5 1/2

658

921

3 1/2

1358

1,900

4 1/2

1138

1,503

5 1/2

867

1,214

6 1/2

625

875

6 5/8

493

690

7

355

497

4 1/2

1665

2,331

5 1/2

1383

1,936

6 5/8

1063

1,488

7

873

1,222

7 3/4

570

798

7

1323

1,852

7 3/4

1022

1,431

8 5/8

627

878

9

450

630

7

1964

2,749

7 3/4

1662

2,323

8 5/8 9

1272 1090

1,779 1,526

8 5/8

2063

2,888

9

1882

2,635

10

1365

1,911

10 3/4

941

1,317 3,400

10

2429

10 3/4

2004

2,806

10

3409

4,772

10 3/4

2985

4,179

12

2209

3,093

13

1527

2,138

10

3743

5,240

14 16

3007 1370

4,210 1,918



Air requirements and nozzle selection Nozzle size selection Nozzles should be selected so that the pressure inside the bit is 40-45 psi. The cab operating pressure will be somewhat higher, depending on the type of drill and CFM of air circulated. Typically, on compressors rated at 65 psi, pressure inside the bit will be 8-15 psi lower than what the cab gauge shows. On drills with 80-100 psi rated compressors, bit pressures can be 25-50 psi lower than the cab gauge reading. The proper procedure for determining the correct nozzle size is as follows: 1. Remove the bit and perform an air test. Record all pressure readings. Be sure to use at least one orifice plate in the air test that will give 40-45 psi at the tool. 2. Determine what the cab pressure is when the tool pressure is 40-45 psi. 3. Re-install the bit with the original nozzles. Run the air compressor and record the cab air pressure. 4. If you do not get the cab air pressure that you saw with 40-45 psi tool air pressure during the air test, continue to install and check different sets of nozzles in the bit until you do get the cab pressure that cor- responds to 40-45 psi in the tool. 5. Once you get the same cab air pressure with nozzles that you got during the air test with 40-45 psi tool pressure, you have found the correct size nozzles to use in the bit.

Tricone bits

How to remove and install air blast nozzles Nozzle removal 1. Use a screwdriver to pry up the head of the nail locking the nozzle into place. 2. When the nail head is pried up, grab the nail with pliers and pull the nail completely out of the bit. 3. Remove the nozzle

Nozzle installation 4. Put the nozzle into the nozzle boss, with the beveled edge to the inside, the flat end to the outside. Place a nozzle nail into the nozzle hole. 5. With a hammer, pound this nozzle nail down until the nail head contacts the bit. 6. DO NOT flatten the head of the nozzle nail against the bit.

The table on the previous page shows approximate bit air pressure that can be expected with the listed nozzles and CFM. This can be used as a starting point for determining correct nozzle size.


177


Air requirements and nozzle selection Procedure for using pressure drop tables 1. Establish maximum operating pressure and air volume delivered for the air compressor being used. consideration should be given to altitude, volumetric efficiency, ambient temperature and mechanical condition of the compressor when establishing these values if actual volume in not known. NOTE: An air test is the best way to determine actual delivery of air volume and pressure. 2. From the table, choose the “air volume delivered” column nearest the actual volume established under item 1. 3. Proceed down the proper “air volume delivered” column to the “bit size range” for the bit being used. 4. Read the air pressure required for forcing air through the bit. The pressure required depends on the size of the air blast nozzles. 5. Select the smallest nozzle diameter available within the given bit size range that can be used without exceeding the maximum operating pressure of the compressor. Note that 10-50 psi should be reserved for a safety buffer and other pressure losses in the system depending on drill type and manufacturer. Example 1 a. Bit size: 7 7/8” b. Air volume delivered: 900 cfm c. Maximum operating pressure rig: 65 psi From the table, select 7/16” nozzle (49 psi), this allows 16 psi for safety buffer and system losses.

Bit size range

5” to 6”

6 1/4” to 7 3/8”

API Pin size

2 7/8” 3 1/2”

3 1/2”

Air course size 3 each

5/16” 3/8” 1/2” 9/16”

200

300

400

500

600

10

22

47

62

77

16

35

47

59

10

25

35

45

18

26

34

11

18

24

5/16”

42

52

62

3/8”

33

43

51

7/16”

27

34

41

1/2”

23

29

33

9/16”

18

23

29

3/8”

27

36

45

7/16”

21

1/2” 7 7/8” to 9”

4 1/2”

28

35

21

27

9/16”

20

5/8” 11/16” 3/4” 3/8”

26

36

46

7/16”

19

27

35

1/2”

21

9/16” 9 7/8” to 11”

6 5/8”

5/8” 11/16” 3/4” 7/8”

Example 2 a. Bit size: 9” b. Air volume delivered: 1200 cfm c. Maximum operating pressure rig: 50 psi From the table, select 11/16” nozzle (39 psi)

1” 7/16” 1/2” 9/16”

Actual air volumes delivered to the bit is a key factor in preventing early bearing failure and providing proper cleaning of the tool. Pressure drops listed above are approximate for use as guidelines only. Actual pressures will depend on bit condition, bearing type, and air piping conditions. Please contact your Atlas Copco Secoroc representative for assistance in determining the best nozzle size for individual bits and mine site condition.

178

27 20

5/8” 12 1/4” to 15”

6 5/8” to 7 5/8”

11/16” 3/4” 7/8” 1” 1 1/8” 1 1/4”


19


Tricone bits Nozzle selection

Air pressure drop across Atlas Copco Secoroc blasthole bits with various nozzle size. Air volume delivered - cubic feet per minute 700

1000

1100

1200

1300

64

71

67

73

79

56

62

67

63

69

75

81

51

59

67

76

84

37

43

49

55

61

67

73

80

31

36

41

47

52

57

62

25

29

34

39

44

50

21

25

29

34

37

41

800

900

55

65

75

42

50

58

66

74

31

38

44

58

58

72

81

61

69

78

48

57

65

73

79

41

48

54

61

34

41

47

51

55

66

75

83

42

49

55

33

39

45

26

32

21

26 20

1400

1500

73

79

1600

1700

1800

1900

69

73

79

55

60

65

71

77

47

51

55

60

65

2000

2100

2200

70

75

79

74

78

2300

2400

2600

2800

3000

71

54

62

70

77

42

50

58

65

72

79

33

39

45

53

60

66

71

77

26

32

38

43

49

54

59

64

68

73

78

19

25

32

36

41

46

49

53

58

62

66

70

74

78

20

24

29

34

39

43

47

51

54

58

62

66

70

19

22

35

41

26

31

36

40

43

47

50

54

57

61

64

68

71

75

79

20

24

26

30

32

35

38

41

44

46

49

52

55

59

63

69

75

19

21

23

25

28

30

33

35

38

40

42

47

52

57

46

53

58

63

69

75 67

72

25

30

18

23

27

33

38

43

47

52

56

60

65

70

75

19

23

27

31

34

38

42

46

50

55

59

63

19

22

25

27

31

34

38

42

46

49

53

57

61

64

68

72

20

23

26

29

32

35

39

42

45

48

52

55

58

62

66

70

19

22

25

28

31

34

37

40

42

45

48

51

53

57

61

65

17

19

21

23

25

27

28

30

33

35

37

40

42

44

47

17

19

21

23

25

27

29

33

37

41

17

19

21

25

27

29

31

17

19

23

25

Above pressure drops are for bits without anti-backflow valves. For bits with anti-backflow valves, add 3 psi.


179


Rock formation & drillability General rock characteristics From the stone age until the present time, man has worked to improve his ability to drill holes in “rock”.The term “rock” generally refers to all the material that forms the essential part of the earth’s solid crust, and includes loose, incoherent masses as well as the very firm, hard and solid masses. Most rocks are aggregates of one or more minerals and are most readily classed according to their method of origin, as igneous, sedimentary or metamorphic.

Tricone bits

periodotitie, are less abrasive, but because of the interlocking nature of the ferro-magnesium minerals, tend to be tougher rocks to drill in spite of the fact they are “softer” and less abrasive. If silicified, (silica has been introduced into the rock through alteration processes) igneous rocks of both extrusive and instrusive types can be very difficult to drill. It is very common for extrusive igneous rocks (volcanics to be silicified.

Sedimentary rocks Igneous rocks Extrusive igneous types: rhyolite, andesite, basalt, dacite, latite, tuff, agglomerate Intrusive igneous types: granite, monzonite, granodiorite, diorite, gabbro, peridotite, syenite Igneous rocks form by solidification from a very hot, molten mass called magma, either on the earth’s surface or below it. Igneous rocks (where they have not been altered after their formation by weathering or other chemical action) can be very hard and tough and possess low porosity. There are two main classes of igneous rocks: “extrusive” and “intrusive”. “Extrusive” igneous rocks are those rocks that are expelled onto the surface of the earth by volcanic activity. Common rocks of this type are basalt, andesite, rhyolite, and latite. “Ash flows” from the rock type called “tuff”. “Agglomerate” is a volcanic rock made up of fragments of other rocks that have been picked up and transported by molten lava as it flows over the land surface. “Extrusive” igneous rocks will generally have a very fine crystalline structure due to the fact that they cooled rapidly from the original molten rock. “Intrusive” igneous rocks are those rocks that solidify below the surface of the ground. They will generally have a coarse crystalline structure. Intrusive rocks that cooled very slowly will have the largest crystal structure, while those that cooled more quickly will have a smaller crystal structure.

Types: conglomerate, sandstone, siltsone, claystone, mudstone, shale, graywacke, limestone, dolomite, coal, phosphate rock, iron formation Sedimentary rocks are formed by an accumulation of sediments in water or air. These sediments may consist of rock fragments or particles of various size, shape and chemical composition to form conglomerate, graywacke, sandstone, siltstone, shale, claystone and mudstone in order of decreasing grain size and roughly in order of decreasing rock hardness. Coal and lignite are formed by the compaction and decomposition of plants which accumulated in tropical swamps. Certain limestones and dolomites are formed from the underwater accumulation of animal remains such as coral and shellfish. Sedimentary rocks also form as the product of chemical action or evaporation. Rocks of this origin include limestone, dolomite, phosphate rock and a variety of salts. Chemically deposited limestone and dolomite can be very “tough” rocks to drill. Iron formation is a “catch-all” term for hard, layered, tough, brittle, very fine grained iron bearing rocks that include taconite, banded iron formation and cherty iron formation. It is of sedimentary origin, occurring throughout the world, and is the source rock for most of the word’s iron ore. Iron formations and their altered or enriched equivalents constitute some of the most difficult of all rocks to drill.

Igneous rocks and their drillabilities Igneous rocks are usually difficult to drill especially where they are fresh and unaltered by weathering or alteration. Low drill bit life and low penetration rates are the general rule (as compared to most common sedimentary rocks). In general, igneous rocks high in quartz contents, i.e., the granite-diorite group, are very hard, brittle and abrasive. Those that contain less quartz and more ferr-magnesium minerals, i.e., gabbro, basalt or 180



Rock formation & drillability

Tricone bits

Metamorphic rocks Types: slate, quartzite, marble, hornfels, schist, gneiss Metamorphic rocks are formed by the action of heat, pressure, and chemical action on pre-existing rocks of any type. Generally, some change in chemical composition has taken place from the original as a result of the heat, pressure, and introduced chemical constituents. Metamorphic rocks can range from very coarse grained to extremely fine grained, depending on the degree of metamorphism. Argillite results from very mild metamorphism of shale, mudstone or claystone. Slate results from an increased level of metamorphism on those same rocks. Quartzite can be formed from sandstone, graywacke or arkose. Quartzite is formed when silica is introduced into sandstone and/or siltstones, and cements the individual grains together. Marble is derived from limestone or dolomite, and is a recrystallization of the original structure. Hornfels is a term applied to fine-grained rocks formed by intense contact metamorphosis (heat, pressure, introduced chemicals) at the borders of igneous rock masses. Hornfels are massive rocks unlike schist or gneiss described below. Schist is a low grade “regional” metamorphic rock which has foliated structure and can be split into thin plates. Some of the original structure of the rock may still be present. There can be mineral segregation, where some minerals may occur in bands, where they did not occur in bands and in the original rock. Gneiss is a high grade to very high grade “regional” metamorphic rock that is generally coarse-grained and banded, in which the bands alternate between “mafic” (iron rich) minerals and “felsic” (non iron) minerals. Similar to various igneous rocks in that they are crystalline and have some of the same mineral constituents, metamorphic rocks are usually difficult to drill. This is caused not only by the hardness and character of the various metamorphic minerals, but by the general interlocking character of mineral crystals which produces a tough rock, difficult to spall.

Rock drilling characteristics General Each of the many types of igneous, sedimentary and metamorphic rocks has its own particular drilling characteristics produced by its mineral composition and grain size. Other factors greatly affecting rock drillability are: rock joints or fractures, bedding or other types of foliation and alteration, which may be simple surface weathering or very complicated chemical alteration processes Blasthole Drilling in Open Pit Mining

such as those which usually are associated with porphyry copper ore bodies. Rock joints occur in virtually every known rock type. Essentially, it is a plane of weakness along which rock tends to break. It can be seen in most quarries and mines. Rock can also be fractured in locations adjacent to blasted areas in mines and quarries. Whatever the agency that causes them, fractures in rock are detrimental to blast hole drilling. They can “rob” return air from the drill hole, thereby reducing ability of the return air supply to remove cuttings from the drill hole; secondly, fractured rock may need to be drilled with less than optimum down pressure and/or rotation speed in order to prevent tooth or insert breakage. Rock drillability can be considerably affected by the angle at which a drill bit intersects bedding or schistosity planes. Drilling in directions parallel to bedding/schistosity planes will usually produce a higher drilling rate and less bit wear than drilling at an angle to bedding/schistosity. Alteration of rock by surface weathering can be seen in most mines and quarries. This process can change a very hard rock such as a granite into a crumbly sandstone. It is caused largely by the action of oxygen, carried by surface water or ground water, on the component minerals of rocks and can extend to depths of 100 m plus. Alteration associated with metallic ore bodies can also affect rock drillabilities by changing the mineral composition of the rock. In general, chemical alteration produces a rock which is softer than the original rock. 181


Rock mechanics data Rock

Amphibolite

Specific gravity

Coompressive strength, UCS Psi

Mpa

3.07

61,335

Poisson’s ration stress vs. strain

Tricone bits Modulus of rigidity

Engineering classification of intact rock

Young’s modulus of elasticity

Psi

Mpa

Psi

GPA

423

6,641,000

45,800

15,080,000

104.0

Based on UCS strength A, very high

Based Young’s compressibility 1 - low

Andesite

2.81

26,535

183

3.944.000

27,200

9,367,000

64.6

B, high

2 - medium

Argillite

2.81

19,720

136

-

-

12,194,500

84.1

B, high

1 - low

Basalt

2.94

44,950

310

4,596,500

31,700

11,295,500

77.9

A, very high

2 - medium

Chert, dolomitic

2.67

29,290

202

3,436,500

23,700

8,149,000

56.2

B, high

2 - medium

Conglomerate

2.67

23,925

165

4,698,000

32,400

11,295,500

77.9

B, high

2 - medium

Diabase

2.94

46,545

321

5,408,500

37,300

13,891,000

95.8

A, very high

1 - low

Diorite

3.01

39,730

274

0.29

6,119,000

42,200

15,515,000

107.0

A, very high

1 - low

Dirorite, augite

2.74

48,285

333

0.25

4,886,500

33,700

12,194,500

84.1

A, very high

1 - low

0.14

Dolotmite

2.60

18,995

131

0.18

2,900,000

20,000

6,902,000

47.6

B, high

2 - medium

Gabbro

3.00

44,805

309

0.33

6,394,500

44,100

17,255,000

119.0

A, very high

1 - low

Granite

2.66

37,700

260

0.2

3,422,000

23,600

8,584,000

59.2

A, very high

2 - medium

Granite, aplitic

2.65

51,185

353

0.26

4,756,000

32,800

11,687,000

80.6

A, very high

2 - medium

Granite, gneissic

2.66

30,305

209

0.02

1,299,200

8,960

2,697,000

18.6

B, high

3 - high

Granite, pre-Cambrian

2.80

-

-

0.27

7,583,500

52,300

11,904,500

82.1

-

2 - medium

Granodiorite

2.74

36,540

252

0.24

4,060,000

28,000

9,947,000

68.6

A, very high

2 - medium

Greenstone

3.02

39,005

269

6,104,500

42,100

15,225,000

105.0

A, very high

1 - low

Hematite ore

5.07

88,015

607

-

-

29,000,000

200.0

A, very high

1 - low

Hornfels

3.19

77,285

533

5,930,500

40,900

13,891,000

95.8

A, very high

1 - low

Limestone

2.68

22,330

154

0.28

3,842,500

26,500

9,874,500

68.1

B, high

2 - medium

Limestone, chalky

1.89

4,205

29

0.02

780,100

5,380

1,609,500

11.1

D, low

3 - high

Limestone, dolomitic

2.78

28,710

198

0.29

5,452,000

37,600

14,094,000

97.2

B, high

1 - low

Marble

2.72

23,925

165

0.3

4,393,500

30,300

11,397,000

78.6

B, high

2 - medium

Marble, taconite

2.71

9,005

62

-

-

6,945,500

47.9

C, medium

2 - medium

Marlstone

2.31

21,895

151

0.11

1,609,500

11,100

3,610,500

24.9

B, high

3 - high

Meta-rhyolite

2.84

18,125

125

4,582,000

31,600

11,397,000

78.6

B, high

2 - medium

Monzonite, Quartz

2.68

22,475

155

-

-

10,498,000

72.4

B, high

2 - medium

Phyllite, green

3.24

18,270

126

4,756,000

32,800

11,092,500

76.5

B, high

2 - medium

0.22

Quartzite

2.65

54,230

374

0.13

4,466,000

30,800

10,150,000

70.0

A, very high

2 - medium

Quartzite, hematitic

4.07

42,485

293

0.2

5,887,000

40,600

14,195,500

97.9

A, very high

1 - low

Sandstone

2.34

477

3

0.1

-

-

57,855

0.4

E, very low

3 - high

Sandstone, argillaceous

2.80

15,225

105

0.05

2,146,000

14,800

4,509,500

31.1

C, medium

3 - high

Sandstone, calcareous

2.60

22,910

158

0.16

3,465,5000

23,900

8,018,500

55.3

B, high

2 - medium

Sandstone, ferriginous

2.60

19,140

132

0.22

2,189,500

15,100

5,553,500

38.3

B, high

3 - high

Sandstone, Navaho, cemented

2.15

12,601

87

-0.09

890,300

6,140

1,508,000

10.4

C, medium

3 - high

-0.03

Sandstone, Navaho, cemented

2.31

13,094

90

Schist, sericite

2.70

23,490

162

1,624,000

11,200

3,146,500

21.7

C, medium

3 - high

3,799,000

26,200

8,700,000

60.0

B, high

2 - medium

Shale

2.81

31,320

216

0.09

3,857,000

26,600

8,439,000

58.2

B, high

2 - medium

Shale, carbonaceous

2.30

16,240

112

0

949,750

6,550

2,015,500

13.9

B, high

3 - high

Shale, siliceous

2.80

33,495

231

0.12

4,422,500

30,500

9,874,500

68.1

A, very high

2 - medium

Siltstone

2.76

37,120

256

3,668,500

25,300

7,714,000

53.2

A, very high

2 - medium

Skarn, garnet-pyroxene

3.28

18,850

130

5,046,000

34,800

12,499,000

86.2

B, high

1 - low

Syenite

2.82

49,935

303

4,103,500

28,300

10,701,000

73.8

A, very high

2 - medium

Syenite, porphytric

2.70

62,930

434

4,393,500

30,300

10,295,000

71.0

A, very high

2 - medium

2.87

38,570

266

4,016,500

27,700

8,903,000

61.4

A, very high

2 - medium

Tactite, epidote

182

0.11



Guides for best bit performance

Tricone bits

I. Exercise care in making-up and breaking-out the drill bit to avoid damaging the bit threads and drill steel. A. After the connection is broken, avoid down pressure on the bit breaker when unscrewing. Hoist the drill steel high enough for the bit to drop from the box connection into the bit breaker. B. Make sure the deck is clean and the bit breaker is properly mounted in its holder. C. Clean the threads on the new bit and on the drill steel, make sure the mating shoulders are clean and a quality “anti-galling” lubricant has been applied. D. Stab carefully - avoid excessive pressure on high angle thread flank. Re-level the machine if the drill stem box doesn’t align with bit pin.

• To insure maximum bearing life, a 40 psi minimum pressure drop across the bit is desirable.

B. Hole cleaning is based on feet/minute of up hole annular velocity.

• Low up-hole velocity causes cuttings to fall back to bottom until they are reground small enough to be carried out of the hole.

E. Always use low torque and slow RPM when making up connection. Mating shoulders should smoothly make up to 1/8” with low torque.

C. Some indications that the hole is not being properly cleaned are:

II.

When a new bit is installed, drill at reduced weight for a short break-in period. Use the 1/3 - 2/3 rules: • 1/3 of normal weight and RPM for 1/3 of the first hole • 2/3 normal weight and RPM for the next 1/3rd of the hole.

• Increase in air pressure.

• Excess of cuttings in the bottom of the hole (more than one foot - after completion of hole and after making a cleaning pass).

• Normal drilling parameters to finish the hole.

• Heavy wear and/or damage indications on shirttails.

A. After the break-in period, bit cones should be checked to be sure that all are about the same temperature. One hot cone generally indicates that the air passage to that particular bearing has become obstruction. If one cone is hot the bit should be inspected before any damage occurs.

D. Some reasons for an increase in air pressure while drilling:

• Fast penetration, not cleaning the holes.

B. Make sure that all assembly grease is blown out of all three cutters. When the air is turned on, air should blow out of the back of each cone.

• Foreign material in the bit, coming from inside the air system, or cuttings coming in through the air nozzles or shirttails.

• Air passages to the bearings becoming plugged with cuttings.

IV.

Turn the air on before lowering the bit to collar the hole. Keep the air on until the bit is finished drilling and is out of the hole. Always rotate the bit when moving in or out of the hole.

III. Provide adequate air to the bit to insure trouble free bearing performance and reduced abrasion wear on cones and shirttails.

A. The compressed air serves two functions: • Air to the bearings, to cool and clean the assembly.

• Hole cleaning to remove cuttings from the blasthole.


• Air volume should produce a minimum of 5,000 linear feet per minute annular return velocity for removal of light cuttings and 7,000 feet per minute for heavy material.

• An increase in torque, torque fluctuations, either hydraulic pressure or amp’s, or an increase in air pressure, are all indications that the hole is not being cleaned.

• Increase in torque indication through higher hydraulic pressure or higher amp meter reading.

A. Make sure the cab gage pressure is at its normal reading and air is circulating through the bit before starting to drill. Inadequate air to the bearings is a principal cause of overheating and early bearing failure.

183


Guides for best bit performance B. Always rotate when coming out of the hole to: • Help clean cuttings from the hole.

• Keep cuttings from entering the bearings around the back face of the cone.

C. Always rotate when going in the hole to:

• Decrease the possibility of damaging the bit or stabilizer on a ledge or other protrusion in the hole.

D. Never use the hydraulic down pressure on the bit to aid in levelling the machine.

• Eliminate the possibility of clogging and jamming of the roller stabilizer rollers. (If used.)

V. Maintain as high a pressure drop across the bit as possible when in wet holes, or when water injection is used.

A. The extra pressure drop helps to keep water and cuttings from entering the bearings.

B. When adding extra drill steel in wet holes, always make three or four cleaning passes to get the bottom of the hole as clean as possible.

C. Never remove any device that the manufacturer has installed from inside the bit.

VI.

Regularly inspect the bit and feel the cones to be sure that all are about the same temperature. One hot cone generally indicates that the passages to that particular bearing have become obstructed.

A. When making this inspection rotate the cones and make sure the bearings are clean and not locked with cuttings.

B. If the cones do not rotate freely, start the air compressor and blow the cuttings from the bearings, then repeat the inspection.

C. Any time the cones cannot be freed, the bit should be taken off for inspection and cleaned.

VII. Never allow the bit to drop while on the end of the drill steel, even for distance of a few inches - dropping the bit can cause cracking of the welds, and/or indentations in the bearing races. Results will be premature bearing failure.

184

Tricone bits

VIII. When a partially dull bit sits idle for a shift or longer, rotate the cones by hand to insure that they turn freely before drilling.

A. If the bit sits idle for any length of time, in freezing conditions, and where water injection is used, water can freeze inside the bearings and air passages. The air temperature from compressor will normally melt the ice if enough time is allowed before starting to drill.

B. The drill steel and bit should be warm before the water injection is used. This will prevent the water from freezing to the cold surfaces.

C. A partially dull bit should never be left down the hole when repairs require lowering the head assembly to the deck. This bit should be substituted by a dull bit to protect the drill steel threads.

D. Procedures for cleaning a bit that has been taken off the drill and will be reused:

• Flush the bearings with water making sure the water is going though each bearing.

• Force air through each bearing.

• Oil bearings and submerge in non-detergent oil.

IX. Occasionally check the air pressure with the bit off to insure that there are no obstructions in the hole swivel or steel.

A. A pressure reading with the bit off can be taken at each bit change and recorded on the drill report. A change from the prior reading will help determine if a new obstruction or new leak has developed.

B. At each bit change any foreign material in the dull but should be noted or investigated.

X. Properly maintain the drill steel and its threaded connections. A bent steel will often cause early failure.

A. A bent drill steel will cause excess loading on one of two cones with resulting bearing failure on those cones.

B. Wear patterns on one side of the drill steel and stabilizer are also indications of the problem.



Guides for best bit performance

Tricone bits

XI. Blasthole bits drill most economically when sufficient weight is applied to cause spalling of the formation.

A. When spalling occurs the cuttings are large and the penetration rate is improved.

XII. Selecting correct rotary speed is usually a matter of trial and error, depending upon the formation being drilled.

B. If a sufficient amount of weight is not applied, the cutting structure will tend to skid along the bottom causing early wear, thus reducing penetration rate and shortening bit life.

C. If too much weight is used for the formation, the cutting structure can be buried to full depth, trapping cuttings beneath the bit. This will cause erosion of the cone metal, prevent the formation from chipping, and reduce the


penetration rate. If cuttings are forced into the cone, bearings can lock up. Heavy weights will also reduce hours of bearing life.

A. Slower RPM’s will reduce the penetration rates and generally increase bit life.

B. Faster RPM’s increase the penetration rates and if excessive RPM’s are used, it tends to shorten bit life. C. Increased penetration rate is usually the result of better spalling of large cuttings.

185

DTH HAMMER SPECIFICATIONS

Industry overview The quarry and mining operations typically have high equipment utilization, drilling 60%, or even up to 80%, of the working day. Companies drilling small to medium blast holes between 85 mm (3 3⁄8") - 152 mm (6") find that performance and service life are critical.

Health/Safety/Education issues are also very important. These operations generally choose premium DTH hammers with resulting faster drill rates and higher reliability.

For those operations drilling large blast holes (greater than 152 mm 6"), performance, reliability, fuel efficiency, servicelife and support are critical. This is often the ideal application for considering premium DTH (Down-The-Hole) hammers with faster drill rates resulting in less time in the hole. This not only reduces labour costs, but lowers wear and tear on expensive drills. For surface mining, presplitting is often carried out to improve slope stability. The pre-splitting holes are often 115 -140 mm (4 ½" - 5 ½") and can be made before the drilling of the production holes.

All mining operation should consider productivity hammers that offer good performance and high reliability. The Secoroc COP Gold DTH hammers incorporate the latest technology and are the most fuel efficient, reliable and highest performance DTH hammers in the market today. If you typically run hammers until they wear out, but still want the possibility to rebuild the hammer for longer service life, then choose Secoroc COP Gold.

The Secoroc solution

Underground mining applications have high cost-per-hour operational overheads, and can generally benefit from service contracts offering on site service and support.

For holes larger than 203 mm (8"), the hammer of choice is Secoroc TD. The TD hammers provide, as the COP Gold, highest possible performance in combination with reliability. The TD hammers are also possible to rebuilt with an economy kit.

Technical specifications Model Product code Product No. General specifications Connection

QL 50

QL 55 QM

QL 60

9705-05-50-00

9705-05-51-08

9706-05-50-00

51983120 English

51997591

Metric

3 1/2 API Reg Pin

English

QL 65 QM

52324258

Metric

3 1/2 API Reg Pin

English

QL 70

QL 80

9706-05-51-08

9708-08-50-00

52324266

Metric

3 1/2 API Reg Pin

English

52315231

Metric

3 1/2 API Reg Pin

English

52083623

Metric

4 1/2 API Reg Pin

English

Metric

4 1/2 API Reg Pin

Outside diameter (in/mm)

4.60

116.8

4.88

124.0

5.44

138.2

5.75

146.1

6.00

152.4

7.13

181.1

Length w/o bit shoulder to shoulder (in/mm)

42.0

1,066.8

42.0

1,066.8

44.6

1,131.8

44.6

1,131.8

44.6

1,131.8

57.5

1,460.5

Length with bit extended (in/mm)

46.3

1,176.3

46.3

1,176.3

49.5

1,256.3

49.5

1,256.3

49.5

1,256.3

63.5

1,611.6

Length with bit retracted (in/mm)

45.3

1,149.4

45.3

1,149.4

48.1

1,220.7

48.1

1,220.7

48.1

1,220.7

61.7

1,567.2

Weight w/o bit (lb/kg)

132.0

60.0

162.0

73.6

200.0

90.9

244

110.9

272.0

123.6

446.0

202.7

Backhead across flats (in)

2 X 3 1/2 AF

2 X 3 1/2 AF

2 X 4 AF

2 X 4 AF

2 X 4 AF

2 X 5 7/8 AF

Minimum bit size (in/mm)

5.13

130.3

5.50

139.7

6.00

152.4

6.50

165.1

6.50

165.1

7.88

Maximum bit size (in/mm)

6.00

152.4

6.00

152.4

8.50

215.9

8.50

215.9

8.50

215.9

12.00

304.8

3.742

95.05

3.742

95.05

4.500

114.30

4.500

114.30

4.500

114.30

5.873

149.17

Piston weight (lb/kg)

31.0

14.1

31.0

14.1

42.6

19.4

42.6

19.4

42.6

19.4

112.0

50.9

Stroke (in/mm)

3.75

95.3

3.75

95.3

3.75

95.3

3.75

95.3

3.75

95.3

3.75

95.3

350.0

24,1

350.0

24.1

350.0

24.1

350.0

24.1

350.0

24.1

350.0

24.1

0.38

9.65

0.38

9.65

0.38

9.65

0.38

9.65

0.38

9.65

0.50

12.70

5,000.0

6,770.0

5,000.0

6,770.0

6,000.0

8,124.0

6,000.0

8124.0

6,000.0

8,124.0

8,000.0

1,0832.0

Bore (in/mm)

Maximum pressure differential (psig/bar) Maximum choke diameter (in/mm) Make-up torque (ft-lb/N-m)

200.2

Air consumption 100 psi/ 6,9 bar (scfm/m3/min)

202.0

5.7

202.0

5.7

305.0

8.6

305.0

8.6

305.0

8.6

166.0

4.7

100 psi (bpm)

1,116

1,116

1,116

1,116

1,270

1,270

1,270

1,270

1,270

1,270

968

968

150 psi/ 10,5 bar (scfm/m3/min)

310.0

8.8

310.0

8.8

431.0

12.2

431.0

12.2

431.0

12.2

437.0

12.3

150 psi (bpm)

1,266

1,266

1,266

1,266

1,370

1,370

1,370

1,370

1,370

1,370

1,050

1,050


422.0

11.9

422.0

11.9

561.0

15.8

561.0

15.8

561.0

15.8

707.0

20.0

200 psi (bpm)

1,401

1,401

1,401

1,401

1,470

1,470

1,470

1,470

1,470

1,470

1,132

1,132


538.0

15.2

538.0

15.2

695.0

19.6

695.0

19.6

695.0

19.6

977.0

27.6

250 psi (bpm)

1,521

1,521

1,521

1,521

1,570

1,570

1,570

1,570

1,570

1,570

1,215

1,215


658.0

18.6

658.0

18.6

832.0

23.5

832.0

23.5

832.0

23.5

1,248.0

35.3

300 psi (bpm)

1,626

1,626

1,626

1,626

1,670

1,670

1,670

1,670

1,670

1,670

1,297

1,297


783.0

22.1

783.0

22.1

973.0

27.5

973.0

27.5

973.0

27.5

1,518.0

42.9

350 psi (bpm)

1,716

1,716

1,716

1,716

1,770

1,770

1,770

1,770

1,770

1,770

1,379

1,379

Operational specifications Feed force (lbs) Rotation speed (rpm)

186

1,500-2,500

1,500-2,500

2,000-3,000

2,000-3,000

2,000-3,000

3,000-4,000

40-60

40-60

30-50

30-50

30-50

20-40


DTH HAMMER SPECIFICATIONS

Some nice picture of Quantum leap hammers to put here

Technical specifications Model Product code Product No. General specifications Connection

COP 44 Gold

COP 54 Gold

COP 54 Gold QM

COP 64 Gold

COP 64 Gold QM

TD 35

9704-03-34

9705-05-34

9705-05-36

97056-05-34

9706-05-36

9703-03-60-00

89001469 English

89001243

Metric

2 3/8 API Reg Pin

English

89001255

Metric

3 1/2 API Reg Pin

English

89000959

Metric

3 1/2 API Reg Pin

English

89000960

Metric

3 1/2 API Reg Pin

English

52312923

Metric

3 1/2 API Reg Pin

English

Metric

2 3/8 API Reg Pin

Outside diameter (in/mm)

3.90

100.0

4.72

120.0

4.90

126.0

5.59

142.0

5.80

146.0

3.13

79.4

Length w/o bit shoulder to shoulder (in/mm)

40.8

1,037.5

44.1

1,119.0

51.5

1,194.0

45.6

1,158.0

49.5

1,258.0

31.4

798.6

Length with bit extended (in/mm)

45.9

1,166

47.9

1,217

47.9

1,217

49.5

1,258

49.5

1,258

35.2

894.1

Length with bit retracted (in/mm)

44.4

1,128.5

49.1

1,247

49.1

1,247

50.8

1,290

50.8

1,290

33.9

862.1

Weight w/o bit (lb/kg)

89.3

40.5

145.2

66.0

166.7

75.6

209.0

95.0

240.3

109.0

65.0

29.5

Backhead across flats (in)

1 3/4 X 2 1/2 AF

Minimum bit size (in/mm)

4.33

110.0

5.28

134.0

5.5

140.0

6.14

156.0

6.5

165.0

3.54

Maximum bit size (in/mm)

5.12

130.0

5.98

152.0

6.00

152.0

7.01

178.0

7.00

178.0

3.93

99.8

Bore (in/mm)

3.23

82.0

3.940

100.00

4.720

120.00

2.521

64.03

Piston weight (lb/kg)

17.4

7.9

33.0

15.0

33.0

15.0

45.1

20.5

45.1

20.5

12.0

5.5

Stroke (in/mm)

4.53

115.0

4.53

115.0

4.53

115.0

4.53

115.0

4.53

115.0

4.00

101.6 24.1

Maximum pressure differential (psi/bar)

89.9

507.0

35.0

435.0

30.0

435.0

30.0

435.0

30.0

435.0

30.0

350.0

Maximum choke diameter (in/mm)

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

0.35

8.89

Make-up torque (ft-lb/N-m)

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

3000

4062


NA

NA

186.0

5.3

186.0

5.3

220.0

6.2

220.0

6.2

142.0

4.0

100 psi (bpm)

NA

NA

1,247

1,247

1,247

1,247

1,350

1,350

1,350

1,350

1,289

1,289

Air consumption


222.0

6.3

285.0

8.1

285.0

8.1

347.0

9.8

347.0

9.8

219.0

6.2

150 psi (bpm)

1,500

1,500

1,364

1,364

1,364

1,364

1,456

1,456

1,456

1,456

1,509

1,509


325.0

9.2

389.0

11.0

389.0

11.0

485.0

13.7

485.0

13.7

288.0

8.1

200 psi (bpm)

1,660

1,660

1,482

1,482

1,482

1,482

1,561

1,561

1,561

1,561

1,699

1,699


428.0

12.1

496.0

14.0

496.0

14.0

635.0

18.0

635.0

18.0

348.0

9.8

250 psi (bpm)

1,820

1,820

1,599

1,599

1,599

1,599

1,667

1,667

1,667

1,667

1,858

1,858


531.0

15.0

607.0

17.1

607.0

17.1

797.0

22.5

797.0

22.5

400.0

11.3

300 psi (bpm)

1,980

1,980

1,716

1,716

1,716

1,716

1,773

1,773

1,773

1,773

1,987

1,987


634.0

18.0

721.0

20.4

721.0

20.4

970.0

27.4

970.0

27.4

444.0

12.5

350 psi (bpm)

2,140

2,140

1,834

1,834

1,834

1,834

1,878

1,878

1,878

1,878

2,086

2,086

Operational specifications Feed force (lbs) Rotation speed (rpm)

1,100-3,300

1,300-4,120

1,300-4,120

1,600-4,400

1,600-4,400

1,500-2,000

25-80

20-70

20-70

15-60

15-60

70-100


187

secoroc grinding

The right tools to get you back on the cutting edge

Every regrinding operation requires its own special tool. The wrong one can easily damage your bits. With Secoroc Grind Matic grinding equipment – complemented by a global service organization – you needn’t worry. Your bits will soon be as good as new.

A machine for every occasion Grinding machine

Button bits

Grind Matic BQ2



Grind Matic Jazz



Grind Matic Manual B



Grind Matic HG



DTH/COPROD bits

Reaming bits

Cross-type bits

Integrals

 

 



Grind Matic BQ2-DTH



Grind Matic Manual B-DTH*





Grind Matic Swing



Grind Matic Senior



 Recommended

188

Can be used

A useful tip: use a Secoroc grinding template, and you’ll see when it’s time for a regrind.

* Can be used for ODEX pilot bits and reaming bits.


secoroc grinding

Grinding

Grind Matic BQ2

Grind Matic BQ2-DTH

Grind Matic Jazz

Semi-automatic grinding machine for button bits

Semi-automatic grinding machine for DTH- and COPROD bits

Grinding capacity Maximum height of drill bit Maximum diameter of drill bit Maximum bit skirt diameter Minimum distance between buttons

Grinding capacity Maximum height of drill bit 650 mm (2'1 5⁄8") Maximum diameter of drill bit 178 mm (7") Minimum distance between buttons 3.5 mm (9⁄64")

Rig-mounted, semi-automatic grinding machine for tapered, threaded, DTH- and COPROD bits

200 mm (7 7⁄8") 127 mm (5") 120 mm (4.75") 3.5 mm (9⁄64")

Technical data Air pressure, max. 7 bar (101.5 psi) Air pressure, min. 8 bar (58 psi) Air consumption 40 l/min Capacity of cooling-fluid tank 22 l Output, spindle motor 1.00 kW Output, driving plate motor 0.15 kW Output, coolant pump motor 0.10 kW Speed, spindle 14 900 r/min Speed, table (50 Hz) 46 r/min Speed, table (60 Hz) 55 r/min Voltage working lighting 12 V Weight, excluding packaging 222 kg (490 Ib) Transport dimension L 1 730 x W 1 030 x H 1 160 mm (68.11" x 40.55" x 43.94") Accessories included in delivery Allen key, 4 mm (1 piece) Centring cup Centring device (1 piece) Coolant concentrate, 0.5 l Grinding templates, spherical and ballistic Grinding wheel, uncoated for centering Protective goggles Operator’s instructions and spare parts list Electrical specifications 220 V 3-phase 50 Hz 220 V 3-phase 60 Hz 380 V 3-phase 50 Hz 415 V 3-phase 50 Hz 415 V 3-phase 60 Hz 440 V 3-phase 60 Hz

Prod. No. 87003801 87003805 87003800 87003802 87003804 87003806

Prod. code 3800-49 3800-60 3800-52 3800-54 3800-62 3800-63

Note: Grind Matic BQ2 must be completed with grinding wheels, centring cups, bitholders (indicate button size and thread dimension) and indexing templates.

Technical data Air pressure, max. 7 bar (101.5 psi) Air pressure, min. 8 bar (58 psi) Air consumption 40 l/min Capacity of cooling-fluid tank 22 l Output, spindle motor 3.00 kW Output, table drive motor 0.15 kW Output, coolant pump motor 0.10 kW Speed, spindle 14 900 r/min Speed, table (50 Hz) 22 r/min Speed, table (60 Hz) 26 r/min Voltage working lighting 12 V Weight, excluding packaging 345 kg (760 lb) Transport dimension L 1 200 x W 1 200x H 1 700 mm (47.24" x 47.24" x 66.93") Accessories included in delivery Coolant concentrate, 0.5 l Grinding templates, spherical and ballistic Puller Protective goggles Operator’s instructions and spare parts list Electrical specifications 220 V 3-phase 50 Hz 220 V 3-phase 60 Hz 380 V 3-phase 50 Hz 415 V 3-phase 50 Hz 415 V 3-phase 60 Hz 440 V 3-phase 60 Hz

Grinding capacity Maximum distance between bit holder and grinding wheel 250 mm (9 7⁄8") Maximum diameter of drill bit 254 mm (10") Minimum diameter of drill bit 35 mm (1 3⁄8") Minimum distance between buttons 3.5 mm (9⁄64") Technical data Air pressure, max. 7 bar (101.5 psi) Air pressure, min. 6 bar (87 psi) Air consumption 25 l/s Coolant container 3l Output, spindle motor 1.00 kW Speed, spindle 15 000 r/min Voltage 24 V Weight, excluding packaging 90 kg (198 lb) Transport dimension L 800 x W 500 x H 700 mm

(2'7 ½" x 1'7 5⁄8" x 2'3 ½")

Accessories included in delivery Box wrench, 11 mm Box wrench, 16 mm Grinding gauge Protective goggles Operator's instructions and spare parts list NOTE:

Prod. No. 87003901 87003904 87003900 87003902 87003905 87003906

Prod. code 3900-49 3900-60 3900-52 3900-54 3900-62 3900-63

NOTE: Grind Matic BQ2-DTH must be completed with grinding wheels, centring cups and bitholders (indicate button size, bit diameter and type of hammer). Optional accessories Prod. No. Prod. code - Auxiliary set for grinding threaded bits (excl. bitholder and templates) 87003939 9500-3939

Grind Matic Jazz must be completed with grinding wheels, centring cups, bitholders and indexing templates. Optional accessories - Anti-freeze kit - Main bit holder for DTH/ COPROD bits - Main bit holder for threaded bits - Mounting bracket for Atlas Copco drill rig - with cabin - without cabin - 3-leg stand - Centring tool

Prod. No. Prod. code 87004315 9500-4315 87004268

9500-4268

87004214

9500-4214

87004628 87004456 87004450 87004465

9500-4628 9500-4456 9500-4450 9500-4465

Grind Matic Jazz, std Prod. No. Prod. code 87004100 9500-4100 incl. main bit holder for threaded bits Grind Matic Jazz, DTH Prod. No. Prod. code 87004300 9500-4300 incl. main bit holder for DTH/COPROD bits


189

secoroc grinding

Grinding


Grind Matic Manual B-DTH

Grind Matic HG

Hand-held portable grinding machine for button bits

Hand-held portable grinding machine for DTH bits

Hand-held grinding machine for button bits

Grinding capacity Maximum diameter of bit skirt Threaded bits, maximum diameter Retrac, maximum diameter Tube drilling, maximum diameter

Grinding capacity Maximum height of drill bit Maximum diameter of drill bit Maximum diameter of bit shank

Grinding capacity Button size

90 mm (3 9⁄16") 127 mm (5") 127 mm (5")* 152 mm (6")*

Technical data Air pressure, max. 7 bar (101.5 psi) Air consumption 15 l/s Coolant container 10 l Idling speed of hand-held grinder 30 000 r/min Speed of bit rotation 0–45 r/min Weight, excluding packaging 55 kg (121.3 Ib) Weight, including packaging 90 kg (198.4 Ib) Transport dimension L 1 200 x W 800 x H 850 mm (3'11 2⁄10" x 2'7 5⁄10" x 2'9 5⁄10") * Large clamping device necessary

506 mm (1'7 7⁄8") 203 mm (8") 170 mm (6 ¾")

Technical data Air pressure, max. 7 bar (101.5 psi) Air consumption (incl. gauge grinding) 25 l/s Air consumption (excl. gauge grinding) 23 l/s Coolant container 10 l Idling speed of hand-held grinder 30 000 r/min Speed of bit rotation 0–45 r/min Weight, excluding packaging 110 kg (253 lb) Weight, including packaging 148 kg (326 lb) Transport dimension L 1 200 x W 800 x H 940 mm (3'11 2⁄10"x 2'7 5⁄10" x 3'1 0⁄10")

Accessories included in delivery Allen key, 4 mm Centring fingers (4 pcs) Grinding templates, spherical and ballistic Hand-held grinder, 30 000 r/min Open end spanner, 14 mm (2 pcs) Protective goggles Operator’s instructions and spare parts list

Accessories included in delivery Allen key, 5 mm Allen key, 6 mm Centring fingers (4 pcs) Grinding belt (4 pcs)* Grinding templates, spherical and ballistic Hand-held grinder (spherical, 30 000 r/min) Open end spanner, 14 mm (2 pcs) Protective goggles Operator’s instructions and spare parts list

NOTE: Grind Matic Manual B must be completed with grinding wheels and bitholders.

*) When ordering gauge grinding unit, Product No. 87002302 / Product code 9500-2302.

Optional accessories - Vibration absorbing sleeve to fit the hand-held grinder - Set of 5 centring fingers

Prod. No. Prod. code

NOTE: Grind Matic Manual B-DTH must be completed with grinding wheels and bitholders.

87001931 87001935


Prod. No. Prod. code 87001890 9424

Optional accessories - Gauge grinding unit complete - Grinding belt for gauge grinding (set of 10 pcs) - Centring fingers (set of 5 pcs), 30 000 r/min - Clamping device for threaded bits

87001935

9500-1935

87002401

9500-2401

Grind Matic Manual B-DTH


190

9500-1931 9500-1935

Prod. No. Prod. code 87002302

9500-2302

87002399

9500-2399

7–20 mm (9⁄32"–25⁄32")

Technical data Air pressure, max. 7 bar (101.5 psi) Air consumption, unloaded 50 l/s Air consumption, loaded (at 6 bar, 86 psi) 42 l/s Hose dimension, air 12.5 mm (½") Hose dimension, water 6.3 mm (¼") Idling speed 17 000 r/min Water flushing pressure, max. 4.5 bar (65.3 psi) Weight, excluding hoses 2.8 kg (6.2 Ib) Accessories included in delivery Adjustable angle connector Allen key, 2 mm Allen key, 3 mm Allen key, 5 mm Claw coupling (6.3 mm) Grease gun Grinding templates, spherical and ballistic Hose (PVC 03) Hose (PVC 6; L = 0.1 m) Hose clamp (7–8.5 mm) Hose clamp (11–13 mm) Hose clamp (26–38 mm) Nipple Pipe (L = 0.3 m) Seal kit Seat Support ring Operator’s instructions and spare parts list Optional accessories - Lubricator - Reconditioning tool for grinding cups

Prod. No. Prod. code 87002750 9500-2750 87002810

Grind Matic HG


9500-2810


secoroc grinding

Grinding

Grind Matic Swing

Grind Matic Senior

Grinding machine for integrals

Grinding machine for integrals

Technical data Air pressure, max. 7 bar (101.5 psi) Air consumption (at 6 bar, 86 psi) 25 l/s Cutting-edge angle 110° Cutting-edge radius 80 mm (3 5⁄32") Gauge grinding arrangement included Hose connections: - Air 12.5 mm (½") - Water 6.3 mm (¼") Idling speed 4 080 r/min Power output 1,10 kW Size of grinding wheel - D x T x H 125 x 63 x 32 mm (47/8" x 215/32" x 1¼") - DI x TI 80 x 50 mm (3 5/32" x 2") Spindle diameter 16 mm (5/8") Weight incl. grinding wheel and 1.5 m water hose 27.5 kg (61 lb)

Technical data Air pressure, max. 7 bar (101.5 psi) Cutting-edge angle, adjustable 90–130° Grinding wheel -DxTxH 200 x 102 x 32 mm (7 7⁄8" x 4" x 1 ¼) - DI x TI 150 x 80 mm (5 7⁄8" x 3 5⁄32") - Cutting-edge radius, adjustable 80-130 mm (3 5⁄32"–5 1⁄8") Idling speed, electric 50 Hz 2 840 r/min Idling speed, electric 60 Hz 1 690 r/min Output 3-phase 1.50 kW Rod hex. max. 25 mm (1") Weight excluding packaging 105 kg (232 lb) Weight including packaging 120 kg (265 lb) Transport dimension L 800 x W 600 x H 650 mm (2'7 ½" x 1'11 5⁄8" x 2'1 5⁄8")

Accessories included in delivery Grinding template Grinding wheel Grind Master Soft Pin wrench Protective goggles Operator’s instructions and spare parts list

Accessories included in delivery Grease gun Grinding template Grinding wheel, Grind Master Hard Protective goggles Socket wrench Wrench Operator’s instructions and spare parts list

Optional accessories Prod. No. - Grinding wheel Grind Master Hard 87002589 - Grinding wheel Grind Master Soft 87002811 - Chuck bushing wear gauge H19 (0,75") 90002667 H22 (0,85") 90002668 H25 (1") 90002669

Electrical specifications 220 V 3-phase 50 Hz 220 V 3-phase 60 Hz 380 V 3-phase 50 Hz 380 V 3-phase 60 Hz 415 V 3-phase 50 HZ 415 V 3-phase 60 Hz 440 V 3-phase 60 Hz

Grind Matic Swing

Prod. code 9550 9500-2811 9131 9132 9133



Prod. No. 87002485 87002493 87135402 87002494 87002488 87002495 87002496

Optional accessories Prod. No. - Grinding wheels Grind Master Hard 87002591 Grind Master Soft 87002813 - Spacer plate for H19 integral 87000519 - Chuck bushing wear guage H19 (0.75") 90002667 H22 (0.85") 90002668 H25 (1") 90002669

Prod. code 9511-49 9427 9511-52 9428 9519 9511-62 0799-8151-63

Prod. code 9552 9500-2813 9500-0519 9131 9132 9133

191

secoroc grinding

Diamond grinding cups for

Centring cups for

Grind Matic HG

Grind Matic BQ2/BQ2-DTH For button size

Product No.

Product code

Dimension, mm

Product No.

Product code

7,0

87002566

9500-2566

7,0 mm

87001040

9500-1040

8,0

87002567

9500-2567

8,0 mm

87000842

9500-0842

9,0

87002568

9500-2568

9,0 mm

87001047

9500-1047

10,0

87002569

9500-2569

10,0 mm

87001041

9500-1041

11,0

87002570

9500-2570

11,0 mm

87000840

9500-0840

12,0

87002571

9500-2571

12,0 mm

87001042

9500-1042

13,0

87002572

9500-2572

12,7 mm

87000839

9500-0839

14,0

87002573

9500-2573

13,0 mm

87001385

9500-1385

15,0

87002574

9500-2574

14,0 mm

87001043

9500-1043

16,0

87002575

9500-2575

14,5 mm

87001443

9500-1443

18,0

87002576

9500-2576

15,0 mm

87001386

9500-1386

20,0

87002577

9500-2577

16,0 mm

87001387

9500-1387

For spherical button bits

7,0

87002579

9500-2579

18,0 mm

87003943

9500-3943

8,0

87002580

9500-2580

19,0 mm

87003944

9500-3944

9,0

87002581

9500-2581

10,0

87002582

9500-2582

11,0

87002583

9500-2583

12,0

87002584

9500-2584

13,0

87002585

9500-2585

14,0

87002586

9500-2586

15,0

87002587

9500-2587

16,0

87002588

9500-2588 9500-2700

For ballistic button bits

7–8

87002700

9–10

87002701

9500-2701

11–12

87002702

9500-2702

For button bit steel removal

13–14

87002703

9500-2703

15–16

87002704

9500-2704

17–18

87002840

9500-2840

19–20

87002841

9500-2841

Grinding wheels for steel grinding Boron nitride – button bits Grind Matic BQ2 Dimension

Product No.

Product code

10–14 mm

87001530

9500-1530

Spacer for 10 mm button

87001631

9500-1631


87001632

9500-1632


87001633

9500-1633


87001634

9500-1634


87001635

9500-1635

192


secoroc grinding

Diamond grinding wheels for button bits Grind Matic BQ2 Grind Matic BQ2-DTH Grind Matic Jazz Grind Matic Manual B Standard diamond-grain wheels Dimension, mm

Product No.

Large diamond-grain wheels

Product code

Dimension, mm

Spherical

Product No.

Product code

Spherical

7

87001028

9500-1028

9

87003969

9500-3969

8

87001026

9500-1026

10

87003970

9500-3970

9

87001389

9500-1389

11

87003971

9500-3971

10

87001023

9500-1023

12

87003972

9500-3972

11

87003406

9500-3406

13

87003973

9500-3973

12

87001024

9500-1024

13

87001339

9500-1339

9

87003974

9500-3974

14

87001025

9500-1025

10

87003975

9500-3975

15

87001384

9500-1384

11

87003976

9500-3976

16

87001027

9500-1027

12

87003977

9500-3977

18

87003964

9500-3964

19

87003966

9500-3966

7

87003407

9500-3407

8

87003408

9500-3408

9

87003409

9500-3409

10

87003410

9500-3410

11

87003411

9500-3411

12

87003412

9500-3412

13

87003413

9500-3413

14

87003414

9500-3414

15

87003415

9500-3415

Ballistic

Ballistic

16

87003416

9500-3416

18

87003965

9500-3965

19

87003967

9500-3967

9

87004359

9500-4359

14.5

87004612

9500-4612

Full ballistic

Grinding templates for button bits

Button bits DTH, spherical

90510753

9129

Button bits DTH, ballistic

90510758

9130


9

9105

D

8

90503414

D/3

Regrind when flat is 173 of button dia.

14

,5

7

Button bits, ballistic

,95

9104

10

90002944

10

Button bits, spherical

Min. 0,5

Product code 12,7

Product No.

193

secoroc grinding

Bitholders for button bits Grind Matic BQ2/Jazz/BQ

Grind Matic Manual B Product No.

Product code

(for clamping device compl. 87000772 / 9500-0772 Grind Matic B)

Threaded bits

Product No.

Product code

Holder R25

87003475

9500-3475

Threaded bit

Holder R28

87003476

9500-3476

R25

87000792

9500-0792

Holder SR28

87003960

9500-3960

R28

87000793

9500-0793

SR28

87003961

9500-3961

R32

87000794

9500-0794

SR32

87003963

9500-3963

R35

87003360

9500-3360

SR35

87003957

9500-3957

R38/T38

87000795

9500-0795

SR38

87003979

9500-3979

T45

87000796

9500-0796

T51

87000802

9500-0802

with 7° taper

87001044

9500-1044

with 12° taper

87001045

9500-1045

Holder R32

87003477

9500-3477

Holder SR32

87003962

9500-3962

Holder SR35

87003956

9500-3956

Holder R38, T38

87003478

9500-3478

Holder SR38

87003978

9500-3978

Holder SR38 retrac, guide

87004081

9500-4081

Holder T45

87003479

9500-3479

Holder TC45

87004569

9500-4569

Holder T51 and retrac

87003521

9500-3521

Holder T60

87004562

9500-4562

Tube bits

Tapered bit

Holder ST58

87003522

9500-3522

Tube bit

Holder ST68

87003523

9500-3523

ST58

87001726

9500-1726

ST68

87001573

9500-1573

Tapered bits Holder 7° taper

87003524

9500-3524

Reaming bit

Holder 12° taper

87003525

9500-3525

64, 76, 89 mm1)

87000798

9500-0798

89, 102, 127 mm1)

87000799

9500-0799

Centering pin for bitholders 9500-0798 and 9500-0799.

87001070

9500-1070

Clamping device for regrinding retrac bits 64–127 mm and TDS bits 89–152 mm (ST58, ST68) without bitholder (to complete 87000772 / 9500-0772).

87001930

9500-1930

Reaming bits Holder 64, 76 and 89 mm reamer

87003526

9500-3526

Holder 89,102 and 127 mm reamer

87003527

9500-3527

Holder SR35 guide bit

87004056

9500-4056

Holder R32 guide bit

87003992

9500-3992

Guide bits

1)

By using the auxillary set part 87003939 (Product No.) / 9500-3939 (Product code), Grind Matic BQ2-DTH can also use the above bit holders for threaded bits.

Grind Matic BQ2-DTH/Manual B-DTH/Jazz-DTH Down-the-hole bits and Coprod bits

Down-the-hole bits and Coprod bits

Product No.

Product code

COP 32

87002420

9500-2420

Grind Matic Manual B-DTH only

COP 34

87003691

9500-3691

Threaded bits* T38

87002148

9500-2148 9500-2149

Product No.

Product code

DHD3.5

87004514

9500-4514

Threaded bits* T45

87002149

DHD340

87002391

9500-2391

Threaded bits* T51

87002147

9500-2147

DHD350

87002390

9500-2390

Threaded bits* ST58

87002158

9500-2158

DHD360

87002389

9500-2389

Threaded bits* ST68

87002154

9500-2154

DHD380

87004523

9500-4523

TD 40

87004604

9500-4604

9500-2401

87004605

9500-4605

* Clamping device for threaded bits

87002401

RC 50 QL40

87004515

9500-4515

QL50

87004033

9500-4033

QL60

87004002

9500-4002

QL80

87004516

9500-4516

COPROD 76

87004414

9500-4414

COPROD 89

87003155

9500-3155

COPROD 102

87004415

9500-4415

COPROD 127

87002396

9500-2396

194


secoroc grinding

Grinding template for cross-type bits

90002611

9102

X-bits

90002612

9103

1 1/2"

3/32"

Cross-type bits

Skivvinkel Wheel

1"

2,4 mm

Product code

110°

Product No.

3/4" 1/2" 1/4"

5 10 15

1/4" 1/2" 3/4"

Ceramic grinding wheels for cross-type bits Product No.

Product code

300 x 19 x 32

87002619

9500-2619

300 x 23 x 32

87002594

9555

38–41 mm

300 x 26 x 32

87002595

9556

43 mm

300 x 28 x 32

87002618

9579

45 mm

300 x 29 x 32

87002597

9558

48–51 mm

300 x 32 x 32

87002616

9577

57 mm

300 x 38 x 32

87002600

9561

76 mm

300 x 52 x 32

87002603

9564

200 x 13 x 32

87002613

9574

200 x 32 x 32

87002615

9576

Bit dimension

Dimension (D x T x H), mm

29 mm 35 mm

Gauge grinding wheels

Grinding template for Integral rods

40

1/8"

9101

30

20

10

3 mm

Product code

90002610

r= 80 mm 3,5/32"

Product No.

110°

Integral rods

0 5 10 15

1/4" 1/2" 3/4"

Ceramic grinding wheels for chisel bit Grinding machine

Dimension, mm

Product No.

Product code

D x T x H (mm)

DI x TI (mm)

Grind Matic Swing

125 x 63 x 32

80 x 50, hard

87002589

9550

”

125 x 63 x 32

80 x 50, soft

87002811

9500-2811

Grind Matic Senior

200 x 102 x 32

150 x 80, hard

87002591

9552

”

200 x 102 x 32

150 x 80, soft

87002813

9500-2813


195

DrillCare

DRILLCare™ Atlas Copco DRILLCare™ is designed with customer care in mind. The focus of this program is to ensure the reliability and highest availability of your drilling equipment, maintaining superior productivity. When your drill is operating to its fullest potential, the lowest total cost of ownership can be achieved. All of the products in the DRILLCare portfolio provide peace of mind for your investment

Extended warranty Peace of mind for three years with no small print. Let us protect your investment. Features • Three years, unlimited operating hours • Follow Atlas Copco maintenance schedule • Atlas Copco genuine parts and selected oils and lubricants • Planned audits

Benefits • Focus on your production • Preventive maintenance • Meet warranty conditions • Assures rig reliability

Service agreements Best-in-class maintenance to ensure reliability and highest availability of your drilling equipment. Features • Total maintenance • Preventive maintenance • Fixed-price repair • Parts-only plans

Benefits • Minimize unplanned repairs • Lowest operating cost • Extended warranty period • Genuine Atlas Copco parts and selected lubricants

Preventive and corrective maintenance kits Atlas Copco genuine parts are manufactured to the same exacting quality standards as your drill rig. Features • Guaranteed performance • Quality inspected and tested • Available through our state-of-the-art distribution system

Benefits • Warranted between scheduled services • Ensured reliability and highest availability • Quick, accurate order fulfillment

Oils and lubricants Atlas Copco oils and lubricants are produced to the exacting specifications required to meet the demands of your drilling application. Features • Designed for the toughest environment • Performance tested • Ensure extended warranty

196

Benefits • Protect your investment • Optimize service life • Save money, minimize breakdowns


DrillCare

Innovative solutions Atlas Copco is continuously developing products and services to maximize the reliability and availability of your drill rig. Features • Hydraulic hose first aid kit • Hydraulic filter cart • Atlas Copco premium air hose • International expertise

Benefits • Limit downtime • Maintain clean, efficient systems • Safety and reliability • Superior productivity

Hydraulic hose first aid kit Each kit provides an immediate replacement for every hydraulic hose on your drill rig. Features • Drill rig specific hoses and adaptors • Complete instructions and accessories • Environmenatally friendly • Wheel or truck mountable

Benefits • Fastest possible fix • First time fix at the jobsite • Spillage control • Highly mobile

Diesel fuel filter cart A portable fuel cleaning system designed to protect your investment. Features • Controls particulate ingression • Prevents water contamination • Easy spin-on replacement elements

Benefits • Maximize usable life of engine components • Minimize downtime • Lower maintenance cost

Hydraulic filter cart A superior contamination control device designed with maximum protection in mind. Features • Multi-stage filtration • Highest quality components • Flexible configurations • Easy spin-on replacement elements


Benefits • Prevents secondary failures • Safety and reliability • Matched to your specific needs • Save time, save money

197

Glossary

198


glossary

Glossary of terms A

Actuator – A motor or cylinder that is being put into motion by the flow of a hydraulic pump. Adapter-Adaptor – (both spellings are accepted) A device used to connect two different sizes or types of threads. It is used to connect rotary head spindles to drill pipe, drill pipe to stabilizers and stabilizers to drill bits. ANFO – Ammonium Nitrate Fuel Oil mixture: explosive most commonly used in blastholes. Angle Drill – Drilling a hole at a 0 to 30 degree angle from vertical (in five degree increments). Annulus – The space between the drill pipe and the outer diameter of the hole made by the bit. Annunciator – An electrical signaling device on a switchboard. API – American Petroleum Institute. ASME – American Society of Mechanical Engineers.

Bit, Roller – Also called a tricone bit. It usually has three conical rollers fitted with steel or tungsten carbide teeth that rip the rock loose using down pressure. Bits – Tools that pulverize formations so that material can be removed from the hole, generally three-blade, three-cone or percussion. Blasthole – A drilled hole used for purposes of excavation rather than exploration, geological information or water wells. Holes are used to load explosives for open pit mining, and are usually limited to 200 feet. Blasting – The act of igniting explosives in a borehole to produce broken rock. Blowdown – Term used when releasing compressed air from the receiver tank on a compressor when the drill is stopped. Blowdown Valve – The valve that opens when the drill is stopped and releases all the air pressure in the receiver tank. Bore – To make a hole in the ground with a drill. Borehole – The hole made by a bit.

ASTM – American Society of Testing Materials.

Box End – Fitting on the female end of a drill pipe. See Pin End.

Auto Lube System – A pump that provides grease to various components of the drill through hoses. It can be manual or computer controlled.

Breakout – Refers to the act of loosening threaded pipe joints, and of unscrewing one section of pipe from another, while coming out of the hole.

B

Bank – Vertical surface of an elevation; also called the face. Beco Thread – A coarse type of thread used on drill pipe. Bench – Work area on the top edge of an elevation. The work area for blasthole drills. Bit, Auger – A type of bit used to drill soft formations. It usually has a series of flutes on the outside. Bit, Claw – A wing-type bit that has multiple flukes. Sometimes called a drag bit. Bit Breaker – A device installed in the centralizer table to hold a bit stationary while the drill pipe is being removed from the bit by reversing the rotation. Also called bit basket. Bit, DHD – A solid, one piece bit with shaped tungsten carbide inserts in the face. Used in percussion drilling. Blasthole Drilling in Open Pit Mining

Breakout Wrench – A wrench, connected to a hydraulic cylinder, used to turn the upper piece of pipe while the lower pipe is being held by the fork chuck or sliding wrench. Bridge – An obstruction in the hole. Usually caused by a caving formation or something falling in the hole. Burden – Distance from the blasthole to the nearest face. Distance measured from the face to a row of holes. The material to be displaced. Buttons – Short, rounded teeth of sintered tungsten carbide inserts which serve as teeth in drill bits used for drilling very hard rock. Butterfly Valve – The adjustable inlet valve of the air compressor.

C

Cable – A strong, heavy steel, wire rope. Also known as wire rope. Used for pulldown

and pullback in the tower. Also used in hoisting. May be rotating or rotation resistant. Cable Reel – A device that holds the electrical power cable on electric driven blasthole drills. Carousel – A rotating device that holds extra drill pipe. It can be moved under the rotary head to add and remove drill pipe from the string, or the rotary head moves over it. Carbide, Tungsten – W2C. A very hard compound used in inserts in rock bits. It has a very high melting point. It is very strong in one direction but very brittle in another. Catwalks – Walkways around a working area of a drill. Cavitation – The pitting of a solid surface by the formation of low pressure bubbles formed in the fluid. Air being allowed into the inlet of pumps. Centralizer Bushing – A circular ring installed around the drill pipe in the drill table to keep the pipe aligned properly with the rotary head. It usually has a replaceable insert in the center. Chain Wrench – A special wrench, consisting of a chain section and a metal vee section, with jaws, that grips the drill pipe and/or the DHD to tighten or loosen the connections. Collar the Hole – Opening at the top of the blasthole; the mouth where rock has been broken by blasting. Usually the first few feet of the blasthole that are cracked and broken. Compressor – An asymmetrical rotary screw driven device for compressing air. May be single- or two-stage, depending on the discharge pressure. Console – The panel that contains most of the drill’s controls. Also called the operator’s panel. Conveyor – Equipment used to carry material to crushers and screens for reduction and separation. Cooler (Hydraulic oil Cooler (HOC), Compressor Oil Cooler (COC)) – All drills have a cooler or coolers for the hydraulic fluid and the compressor oil. The engine radiator is also sometimes referred to as an engine cooler. Coring – The act of procuring a sample of the formation being drilled for geological information purposes. 199

Glossary

Coupling – A connector for drill rods, pipe or casing with identical threads, male or female, at each end. Cribbing – A set of wooden ties or metal plates used to add surface area to the jack pads to prevent the pad from sinking into the ground. Also called blocking. Crown Sheaves – The upper sheaves in a tower that supports the cable that connects to the rotary head. Crosshead – The outer metal can surrounding the leveling jack cylinders. The crosshead slide is the lower portion that connects to the bottom of the cylinders and the crosshead cap is the flanged piece on top of the crosshead. Crusher – Device used to reduce broken rock to a smaller fragment size. Cut (verb) – Process of excavating material to lower the level of part of an elevation. Cut (noun) Part of an excavation of a specified depth and width. Cuttings – Particles of formation obtained from the hole during drilling operations.

D

Decking – Process of alternating explosives with inert material in a blasthole to properly distribute explosives or reduce vibrations. Also refers to the metal catwalks around the outside of the drill. Delay Interval – Elapsed time between detonation of individual blastholes in a multiple hole blast. Derrick – A tall framework over a drilled hole used to support drilling equipment. The part of the drill that contains the feed system and the rotary head. See Tower and Mast.

Dressing a Bit – Sharpening DHD drill bits with a grinder to shape the carbides. Drifter – An out-of-the-hole drill that rotates the drill rod and provides a percussive force, by means of a striking bar, through the rod to the bit. Drill – A machine for drilling rock or unconsolidated formations. Also called a rotary drill. The act of boring a hole in the ground. Drill Collar – A heavy, thick-walled section of pipe used to add drilling weight to the bit and stabilize the drill string. Drill Rod – See Drill Pipe. Hollow, flush-jointed, coupled rods used on small percussion type rock drills. Drill Pipe – Hollow tubing, specially welded to tool joints. Drill/Propel Valve – A switch that shifts the diverter valves to allow pump flow to go from drill functions to propel motors. Drill String – The string of pipe, including subs, stabilizers, collars and bit, extending from the bit to the rotary head, that carries the air or mud down to the bit and provides rotation to the bit. Driller (Operator) – The employee directly in charge of a drill. Operation of the drill is their main duty. Drill Table – The area at the bottom of the tower that contains the centralizer bushing or master bushing that the drill pipe travels through. Dust Collector – A vacuum device with a hose attached to the dust hood that pulls cuttings away from the hole and deposits them to the side of the drill.

Fish – An object accidentally lost in the hole. Fishing – Operations on the drill for the purpose of retrieving the fish from the hole. Fishing Magnet – Magnet run in the hole on non-metallic line, to pick up any small pieces of metal. Fishing Tools – Tools of various kinds run in the hole to assist in retrieving a fish from the hole. Overshots fit over the pipe while taps fit inside the pipe. Flats – Machined areas on the side of drill pipe or other components where wrenches can be installed to hold or break the joints. Some pipe have two flats, others have four flats. Floor – Level area at the base of a bank or face. Fork Chuck – The handheld or “flop-down” wrench used to hold the top of the pipe on the drill table while adding or removing other pipe.

H

Hammer – A different name for a Down Hole Drill. Hammer Bushing – Split bushings installed in the drill table to allow the DHD to start the hole in a straight line. It is removed once the DHD is below the table. Also called DHD bushings. Haul Distance – Distance material has to be moved, such as from a cut to a fill. Hauling Equipment – Trucks and other conveyances for moving material. Also called haul trucks. Hazard – Any condition of the drilling equipment or the environment that might tend to cause accidents or fire.

F

Hoist – Device used to pick up drill pipe and other heavy objects. See Winch.

Feed Cable – Cables, anchored on the top and the bottom of the tower, that pass through the traveling sheave block and connect to the top and bottom of the rotary head. They are adjusted by tightening the threaded rods on each end.

Hoist Plug – A lifting device installed in the box end of a tool. Opposite of lifting bail.

Dip – The angle between a horizontal plane and the plane of the ore vein, measured at right angles to the strike.

Feed Chain – Heavy duty chain links connected to the rotary head through upper and lower sprockets and the traveling sheave block. They are adjusted similar to a cable.

Hose, Drilling – Connects rotary head to top of hard piping to allow movement of rotary head. Also called standpipe hose.

Diverter Valve – A two position, three-way, valve that allows one hydraulic pump to perform two separate functions.

Fill – Process of moving material into a depression to raise its level; often follows the cut process.

DHD – Down Hole Drill. An air driven, piston powered device for drilling hard rock. It is also called a hammer. DHD Bushings – The split bushings used to maintain alignment of the DHD while passing through the drill table. See Split Bushings. Differential Pressure – The difference in pressure between the inlet and outlet of a component, i.e., a cooler.

200

Face – Vertical surface on an elevation. Also called bank.

Hole – A bore made by rotating a bit into the ground.

Hydraulic Cylinders – Double acting cylinders that are extended and retracted to perform various functions on a drill. They are powered by hydraulic fluid from a pump. Blasthole Drilling in Open Pit Mining

glossary

Hydraulic Motors – Piston or vane type motors, driven by hydraulic pumps, that rotate various devices on a drill. Hydraulic Pumps – Piston, vane and gear type hydraulic pumps that provide flow for the various actuators on the drill. Hydrostatic Head – The pressure exerted by a column of fluid, usually expressed in pounds per square inch.

I

Inclinometer – An instrument for measuring the angle to the horizontal or vertical of a drill hole or vein. I.W.R.C. – Abbreviation for Independent Wire Rope Center. This refers to the type of construction of wire rope. This wire rope center is in effect a separate wire rope in itself that provides a core for the line and prevents it from crushing or breaking. Interstage Pressure – The air pressure present between stages of a two-stage compressor while the compressor is making air.

J

J Wrench – Specially shaped wrench to fit the backhead of a DHD. Used to hold a DHD on the table or to remove the backhead from the wear sleeve.

K

Kelly Bar – A fluted or square drill pipe that is turned by a rotary table using a set of pins.

L

Leveling Jacks – Hydraulic cylinders mounted in a crosshead that raise and lower the drill. Also referred to as outriggers or stabilizers. Lifting Bail – A threaded cap for picking up pipe, bits, DHDs and stabilizers. It screws on the pin end. Some bails have a swivel hook while others have solid tops. Opposite of hoist plug. Loaders – Large, front end bucket equipment used to pick up material for loading in various types of hauling equipment.

M

Main Frame – The welded component of a track mounted drill. The truck frame on a wheeled drill. Main Shaft (axle) – The tube connecting the tracks of a blasthole drill to the main frame. Makeup – The act of tightening threaded joints. Making a connection. Blasthole Drilling in Open Pit Mining

Making Hole – The act of drilling. Making Up a Joint – The act of screwing a joint of pipe into another joint or section of pipe. Manifold – A pipe or chamber that has several openings for hose connections.

Pipe Dope – Special lubricant used to protect the threads on pipe joints. See Thread Lube. Pipe Support – A device that holds the lower section of pipe in place while connecting to the next joint with the rotary head when angle drilling. Also called rod support.

Mast – A vertical structure. See Derrick.

Pit – An excavation in the ground for the removal of mineral deposits.

Micron -:- Mu – A unit of length equal to one millionth of a meter, or one thousandth of a millimeter. About 4/100,000 of an inch.

PLC – Programmable Logic Controller. A device that monitors many aspects of a drill’s operation.

Mid-Inlet Swivel – Device for removing cuttings from the hole while drilling with reverse circulation equipment.

Potable Water – Water that is safe to drink.

Mine Plan – Plan for making cuts and creating elevations, benches for efficient removal of material. The mine plan considers a variety of factors, including the type and location of material, the size and number of shovels, loaders, and hauling equipment, haul distances, blasthole patterns, etc.

Powder Factor/Specific Charge – Relationship between the weight of explosives in a blasthole and the volume of materials to be displaced. It is measured in pounds per cubic yard or kilograms per cubic meter. Power Pack Base – The welded channel frame that contains the prime mover, the compressor and the hydraulic pumps and gearbox.

O

Power Pack – The complete sub-assembly of base, engine, compressor, and hydraulic drive.

Open Hole – Any uncased portion of a hole.

Presplitting – Process of drilling a line of small diameter holes spaced relatively close together, generally before drilling a production blast, and loaded with light explosive charges to create a clean, unbroken rock face.

Oscillation Yoke – The beam connecting each track of a blasthole track drill with the main frame that allows the tracks to move independently up and down.

Operator – The person who performs the drilling operation with the drill. See Driller. Overburden – Any unconsolidated material lying on top of the bedrock or the coal seam.

P

Parasitic Load – The load imposed on the engine by the direct connection of the compressor and main pump drive during starting. Pattern – Layout and distances between blastholes, specifically including burden and spacing. Penetration Rate – Speed at which a bit advances while drilling, usually measured in feet per hour. Instantaneous or drilling penetration rate is the rate only while drilling. Overall penetration rate is the same as the production rate (see production rate).

Production Rate – Penetration during a given reporting period. This rate includes all lost time including maintenance, breakdowns, long moves, inclement weather, etc. Propel – To cause to move forward or onward. To drive or tram. Protectors, Thread – Steel or plastic covers to cover the box and pin ends of drill pipe when they are not being used. Pump, Water Injection – Pump used to pump water into the drill air stream to keep the dust settled and to assist in flushing the hole. Pullback – The force available to remove the drill string from the hole.

Percussion Drill – Drill that chips and penetrates rock with repeated blows.

Pulldown – Force exerted on the drill bit by the thrust of the drill rig and from the weight of the drill string.

Pin End – Fitting on male end of drill pipe. See Box End.

Q

Pioneer Work – Drilling in rough, broken or inclined areas. Removing the original layers of dirt and rock.

Quick Fill – A centralized service station that connects to various systems on the drill to allow remote filling of engine oil, compressor oil and hydraulic oil. 201

Glossary

R

Raise – A mine opening, like a shaft, driven upward from the back of a level to a level above, or to the surface.

Sliding Fork – A wrench that slides around the flats of the drill pipe to hold the section lower. Controlled by hydraulic cylinder(s). Used in place of a fork chuck.

Reamer – Bit-like tool, generally run directly above the bit to enlarge and maintain a straight hole.

Slips – Used in the rotary table to hold and break out drill pipe. Also used to hold casing in the table.

Reservoir –The tank used for storing the hydraulic oil used in the hydraulic system.

Spacing – Distance between blastholes measured parallel with the face.

Reverse Circulation Drilling – Using a double wall pipe to force air/water down the hole and removing the cuttings between the two pipes. See Mid-Inlet Swivel.

Spear – Tools of various design that are screwed or wedged inside of bits, pipe, etc., that are lodged in the hole. See Fishing Tools.

Rod Changer – A device that holds extra drill rod (pipe). See Carousel.

Spindle – The short section of pipe that rotates within the rotary head, and protrudes out.

Rotary Drilling – The method of drilling that depends on the rotation of a column of pipe to the bottom of which is attached a bit. Air or fluid is circulated to remove the cuttings.

Speed Switch – An electronic device that changes states when the engine reaches a certain speed. Used to control dual oil pressure switches.

Rotary Head – A movable gearbox used to provide rotation to the drill string. It is connected to the feed chains or cables on each end and to the drill string through the spindle.

Split Bushings – The removable bushings that allow the DHD or Stabilizer to pass through the drill table while drilling a straight hole. See DHD Bushings.

S

Safety Hook – Attached to the end of a hoist line to secure the hoist plug or lifting bail. Has a safety latch to prevent the load from slipping off the hook. Scales – Equipment used to determine the weight and value of material being transported from a quarry. Screens – Devices used to separate broken material into groups of similar size. Shock Sub – A device used to isolate the shock of drilling from the rotary head. It is made of hard rubber layers mounted inside of steel outer rings. Single Pass Drill – Drill rig with a long tower that permits drilling a blasthole without stopping to add drill pipe (rod). Uses a Kelly in place of regular pipe. Uses a rotary table to turn the Kelly instead of a rotary head. Stemming – Material of a specified depth added on top of a powder column to confine the blasthole and make the explosion more efficient. Strip Mine – A large section of land used to remove coal deposits.

Stabilizer, Drill Pipe – Heavy -walled pipe having special spiral or fluted ribs extending around the diameter, within 1/8 “to 1/4” of hole size. Most stabilizers are fitted just above the bit, while in-line stabilizers keep the hole straight. Standpipe – Part of the circulating system. The hard and flexible piping from the main valve to the flexible hosing leading to the rotary head. Water injection, DHD oil and foam are injected into this line. Static Water Level – The distance from the top of ground down to the standing water level. Strike –The bearing of the outcrop of an inclined bed or structure on a level surface. See Dip. Stuck In The Hole – Refers to drill pipe inadvertently becoming fastened in the hole. Subdrilling – Bottom portion of a blasthole drilled below the floor level to permit upward displacement of material and thereby prevent a toe at the bottom of a face.

Swivel – A coupling on top of the rotary head to allow the spindle to rotate while the main hose remains stationary.

T

Table Drive – Drill design that locates the drill pipe rotation mechanism on the drill deck in a stationary position instead of using the rotary head. Threaded and Coupled Casing (T&C) – Steel casing using a coupling between each section of pipe. Thread style is right hand, fine thread. Thread Lube – A special compound used to lubricate the threads of drill pipe. See Pipe Dope. Tongs – A type of wrench used to make up and break out drill pipe using external forces, such as hydraulic cylinders or cables. Tool Joint – A drill pipe coupler consisting of a pin and box of various designs and sizes. Deephole drills normally use API style threads, while blasthole drills normally use Beco style threads. Top Head Drill – Drill design that locates the drill pipe rotation head in the drill tower. It moves up and down with the drill string. See Rotary Head. Torque – A turning or twisting force. A moment caused by force acting on an arm. A one pound force acting on a one-foot arm would produce one lb-ft of torque. Tower – A tall, slender structure used for observation, signaling or pumping. Term used to indicate the derrick on a blasthole drill. See Derrick and Mast. Turning To The Right – Slang term for making a hole. Tram – A cable car or a four-wheeled open box in a coal mine. See Propel. Trammed – To move in a tram. Tramming – Process of moving a drill. See Propelling. Traveling Sheave Block – A series of sheaves, connected to the feed chains or cables, that are moved up and down the derrick by the feed cylinders.

Shot – A charge of high explosives deposited in a series of holes to shatter the rock.

Sub – A coupling with different type or diameter of threads at either end. The term pin denotes a male thread, and box, a female thread. To connect two components with different threads. See Adapter.

Twist Off – To twist a joint of pipe in two by excessive torque applied by the rotary head or rotary table.

Shutdown – A term that can mean the end of the shift or workday or an unplanned stopping of the drill due to a system failure.

Supercharge Pressure – Inlet oil pressure to the main pump(s) that has been pressurized to prevent cavitation.

UL88 – The pneumatic valve that controls pressure and volume on a high-pressure compressor system.

202

U


glossary

Undercarriage – The means of moving a track type vehicle. It contains the track frame, rollers, grousers, rock guards, drive sprocket, propel motors and planetary drive. Uphole Velocity – The speed (in feet per minute) that the cuttings travel out of the hole. This is dependent on the bit size, the compressor size and the pipe size.

W

Washpipe – Hard surfaced steel tubes inserted in swivels to allow rotation of drill string and prolong life of packing. They are replaceable in most swivels.

Weight On Bit – In rotary drilling, a specified weight is required on the bit for maximum performance. A gauge on the console is calibrated to correspond to the drill string weight. Winch – A stationary hoisting machine having a drum around which a rope is wound. Wiper, Pipe – An annular rubber disk for wiping drill pipe clean of cuttings when it is being withdrawn from the hole. Wire Rope – Rope made of twisted strands of steel wire. Also called cable.

Water injection – A method of rotary drilling where water is dispersed in the air while drilling. Blasthole Drilling in Open Pit Mining

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Atlas copco

Where to find us

For more information, please contact your local Atlas Copco Customer Center. Area Angola Argentina Australia Austria Belgium Bolivia Brazil Bulgaria Canada Chile Croatia China Colombia Cyprus Czech Republic Denmark Egypt Estonia Finland France Germany Ghana Great Britain Greece India Indonesia Iran Ireland Italy Japan Kazakhstan Kenya South Korea Latvia Lithuania Macedonia Malaysia Mexico Mongolia Morocco Namibia Netherlands New Zealand Nigeria Norway Pakistan Peru Philippines Poland Portugal Russia Saudi Arabia Singapore Slovenia South Africa Spain Sweden Switzerland Taiwan Thailand Turkey United Arab Emirates Ukraine USA Venezuela Vietnam Zambia Zimbabwe

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For further information, please visit www.atlascopco.com or contact Atlas Copco AB, SE-105 23 Stockholm, Sweden, Telephone: + 46 (0)8 743 80 00 Telefax: + 46 (0)8 702 21 29.

204


We’re redrawing the line between productivity and innovation.

Efficient and effective drilling

Atlas Copco has worked with the drilling business through the peaks and the troughs, both literally and figuratively. Not only have we been producing air pressure and power for the drilling industry for many years, we’ve been at the forefront of drill production too. We know that drilling takes time and that time is money. Whatever kind of drilling is required, we’ve got the right stuff.

Introducing the new and expanded line of the Pit Viper Series drills from Atlas Copco. The venerated PV-351, PV-275, and PV-271 are being joined by the all new PV-235 series. And throughout the line, we’re crafting a better user experience by improving your comfort, control and visibility. Plus, our new power systems add to your bottom line with increased fuel efficiency. So, whether you’re mining precious metal or mineral, follow the line and mine with us.

www.atlascopco.com

Copyright © 2008 Atlas Copco Drilling Solutions Inc.

Increase your productivity with Atlas Copco !

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Atlas Copco

Committed to Productivity


• World leader in blasthole drilling technology and innovation • Designed and built to optimize productivity and performance • Supported by a global network of dedicated service personnel • Genuine parts available through state-of-the-art distribution system

2009

Find out more at www.atlascopco.com/blastholedrills

Printed matter no. 9881 0169 01

• Quick link to drill rigs at www.atlascopco.com/ blastholedrills

Blasthole Drilling in Open Pit Mining

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